Herb & supplement monograph
Collard Drug Interactions, Uses, Effectiveness, Safety & More
What is this page for?
First and foremost: how Collard interacts with medications. The heart of this page is the interaction list — every drug Collard is known to interact with, and how serious each one is.
But these pages have grown well beyond that into a full monograph — what Collard is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy
Check Collard against your medication
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Interaction report
Drugs that interact with Collard
86 medications have a known interaction with Collard, graded by severity. Select any drug for the full evidence-based detail.
Don’t want to scroll the list? Just ask.
Tell us the medications you take and we’ll check each one against Collard using our pharmacist-reviewed interaction data.
AI summaries are generated from our Collard interaction data for education only — always confirm with your pharmacist. How we use AI
2,830 drugs
No drugs match “”.
AcarboseGlucobay, Prandase, Precose
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Acarbose interaction Acarbose drug page: uses, dosage & side effectsAcetohexamideDymelor
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Acetohexamide interactionAlbiglutideTanzeum
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Albiglutide interactionAlogliptinNesina
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Alogliptin interaction Alogliptin drug page: uses, dosage & side effectsAlogliptin, MetforminKazano
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Alogliptin, Metformin interactionAlogliptin, PioglitazoneOseni
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Alogliptin, Pioglitazone interactionAntidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) InhibitorGlyxambi
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Antidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) Inhibitor interactionCanagliflozinInvokana
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Canagliflozin interaction Canagliflozin drug page: uses, dosage & side effectsCanagliflozin, MetforminInvokamet
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Canagliflozin, Metformin interactionCanagliflozin, Metformin HydrochlorideInvokamet XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Canagliflozin, Metformin Hydrochloride interactionChlorpropamideChlorpropam, Diabinese
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Chlorpropamide interactionDapagliflozinFarxiga
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Dapagliflozin interaction Dapagliflozin drug page: uses, dosage & side effectsDapagliflozin Propanediol, MetforminXigduo XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Dapagliflozin Propanediol, Metformin interactionDapagliflozin Propanediol, Saxagliptin HydrochlorideQtern
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Dapagliflozin Propanediol, Saxagliptin Hydrochloride interactionDapagliflozin, Metformin Hydrochloride, Saxagliptin HydrochlorideQternmet XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Dapagliflozin, Metformin Hydrochloride, Saxagliptin Hydrochloride interactionDasiglucagon HydrochlorideZegalogue
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Dasiglucagon Hydrochloride interaction Dasiglucagon Hydrochloride drug page: uses, dosage & side effectsDulaglutideTrulicity
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Dulaglutide interaction Dulaglutide drug page: uses, dosage & side effectsEmpagliflozinJardiance
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Empagliflozin interaction Empagliflozin drug page: uses, dosage & side effectsEmpagliflozin, Linagliptin, Metformin HydrochlorideTrijardy XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Empagliflozin, Linagliptin, Metformin Hydrochloride interactionEmpagliflozin, MetforminSynjardy
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Empagliflozin, Metformin interactionEmpagliflozin, Metformin HydrochlorideSynjardy XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Empagliflozin, Metformin Hydrochloride interactionErtugliflozinSteglatro
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Ertugliflozin interaction Ertugliflozin drug page: uses, dosage & side effectsErtugliflozin, Metformin HydrochlorideSegluromet
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Ertugliflozin, Metformin Hydrochloride interactionExenatideBydureon, Byetta
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Exenatide interaction Exenatide drug page: uses, dosage & side effectsExenatide SyntheticBydureon BCISE
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Exenatide Synthetic interaction Exenatide Synthetic drug page: uses, dosage & side effectsGliclazideDiamicron
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Gliclazide interactionGlimepirideAmaryl
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Glimepiride interaction Glimepiride drug page: uses, dosage & side effectsGlipizideGlucotrol, Glucotrol XL
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Glipizide interaction Glipizide drug page: uses, dosage & side effectsGlipizide, MetforminMetaglip
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Glipizide, Metformin interactionGlucagonBaqsimi, Glucagon
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Glucagon interaction Glucagon drug page: uses, dosage & side effectsGlucoseIV Glucose
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Glucose interactionGlyburideAlbert Glyburide, Diabeta, Glycron, Glynase, Glynase PresTab, Micronase +1 more
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Glyburide interaction Glyburide drug page: uses, dosage & side effectsGlyburide, MetforminGlucovance
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Glyburide, Metformin interactionInhaled InsulinExubera
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Inhaled Insulin interactionInsulinNovoRapid Insulin
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin interactionInsulin (bovine)Hypurin Bovine Neutral
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin (bovine) interactionInsulin (human)Afrezza, Novolin 70/30, Novolin L, Novolin N, Novolin R
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin (human) interaction Insulin (human) drug page: uses, dosage & side effectsInsulin (pork)Hypurin Porcine Neutral, Lente Iletin II, NPH Iletin, NPH Iletin II, Pork Actrapid, Regular Iletin +1 more
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin (pork) interactionInsulin (rdna)Actrapid, Humalog, Humalog Mix 75/25, Humulin 50/50, Humulin 70/30, Humulin L +8 more
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin (rdna) interaction Insulin (rdna) drug page: uses, dosage & side effectsInsulin AspartFiasp
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Aspart interaction Insulin Aspart drug page: uses, dosage & side effectsInsulin Aspart, Insulin DegludecRyzodeg 70/30
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Aspart, Insulin Degludec interactionInsulin DegludecTresiba
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Degludec interaction Insulin Degludec drug page: uses, dosage & side effectsInsulin Degludec, LiraglutideXultophy 100/3.6
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Degludec, Liraglutide interactionInsulin GlargineBasaglar, Lusduna, Semglee
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Glargine interaction Insulin Glargine drug page: uses, dosage & side effectsInsulin Glargine (rdna)Lantus
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Glargine (rdna) interaction Insulin Glargine (rdna) drug page: uses, dosage & side effectsInsulin Glargine RecombinantToujeo Solostar
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Glargine Recombinant interactionInsulin Glargine, LixisenatideSoliqua 100/33
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Glargine, Lixisenatide interactionInsulin Glulisine (rdna)Apidra
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Glulisine (rdna) interaction Insulin Glulisine (rdna) drug page: uses, dosage & side effectsInsulin Human, Sodium ChlorideMyxredlin
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Human, Sodium Chloride interaction Insulin Human, Sodium Chloride drug page: uses, dosage & side effectsInsulin LisproAdmelog, Admelog Solostar
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Lispro interaction Insulin Lispro drug page: uses, dosage & side effectsInsulin Lispro RecombinantHumalog Kwikpen
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Lispro Recombinant interactionInsulin Lispro-aabcLyumjev
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Lispro-aabc interactionInsulin DetermirLevemir
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Insulin Determir interaction Insulin Determir drug page: uses, dosage & side effectsLinagliptinTradjenta
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Linagliptin interaction Linagliptin drug page: uses, dosage & side effectsLinagliptin, Metformin HydrochlorideJentadueto XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Linagliptin, Metformin Hydrochloride interactionLiraglutideVictoza
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Liraglutide interaction Liraglutide drug page: uses, dosage & side effectsLiraglutide RecombinantSaxenda
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Liraglutide Recombinant interaction Liraglutide Recombinant drug page: uses, dosage & side effectsLixisenatideAdlyxin
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Lixisenatide interaction Lixisenatide drug page: uses, dosage & side effectsMetforminGlucophage, Metformin
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Metformin interaction Metformin drug page: uses, dosage & side effectsMetformin HydrochlorideRiomet ER
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Metformin Hydrochloride interactionMetformin XrGlucophage XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Metformin Xr interactionMetformin, LinagliptinJentadueto
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Metformin, Linagliptin interactionMetformin, RosiglitazoneAvandamet
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Metformin, Rosiglitazone interactionMetformin, SitagliptinJanumet, Janumet XR
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Metformin, Sitagliptin interactionMiglitolGlyset
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Miglitol interaction Miglitol drug page: uses, dosage & side effectsMuraglitazarPargluva
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Muraglitazar interactionNateglinideStarlix
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Nateglinide interaction Nateglinide drug page: uses, dosage & side effectsPioglitazoneActos
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Pioglitazone interaction Pioglitazone drug page: uses, dosage & side effectsPramlintideSymlin
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Pramlintide interaction Pramlintide drug page: uses, dosage & side effectsRepaglinideGlucoNorm, Prandin
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Repaglinide interaction Repaglinide drug page: uses, dosage & side effectsRosiglitazone MaleateAvandia
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Rosiglitazone Maleate interaction Rosiglitazone Maleate drug page: uses, dosage & side effectsSaxagliptinOnglyza
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Saxagliptin interaction Saxagliptin drug page: uses, dosage & side effectsSaxagliptin, Metformin XrKombiglyze
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Saxagliptin, Metformin Xr interactionSemaglutideOzempic, Rybelsus, Wegovy
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Semaglutide interaction Semaglutide drug page: uses, dosage & side effectsSimvastatin, SitagliptinJuvisync
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Simvastatin, Sitagliptin interactionSitagliptinJanuvia, Zituvio
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Sitagliptin interaction Sitagliptin drug page: uses, dosage & side effectsSitagliptin, MetforminZituvimet
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Sitagliptin, Metformin interactionSotagliflozinInpefa
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Sotagliflozin interactionTirzepatideMounjaro, Zepbound
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Tirzepatide interaction Tirzepatide drug page: uses, dosage & side effectsTobutamideMobenol
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Tobutamide interactionTolazamideTolinase
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Tolazamide interaction Tolazamide drug page: uses, dosage & side effectsTolbutamideOrinase
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Tolbutamide interaction Tolbutamide drug page: uses, dosage & side effectsTroglitazoneRezulin
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Troglitazone interactionVildagliptinGalvus
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Vildagliptin interactionPioglitazone, MetforminActoPlus Met
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Pioglitazone, Metformin interactionRosiglitazone, GlimepirideAvandaryl
Moderate
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels.
Read the full Collard + Rosiglitazone, Glimepiride interaction
Read The List Like a Pharmacist
What Severity, Likelihood & Evidence Mean
Severity — How Serious It Can Be
- Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
- Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
- Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
- No known interaction. Checked against our sources with nothing documented — not the same as proven safety.
Likelihood — How Well It’s Documented
- Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
- Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
- Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
- Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Where This Data Comes From
- Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
- Each drug listed above links to the full report for that exact Collard combination — clinical detail, likelihood, evidence level, and citations.
- Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture
The kinds of drugs Collard affects
Every type of medication (drug category) Collard is known to interact with. Open any category for the detail — or search your exact drug in the checker above.
All 1 drug category Collard interacts with
Antidiabetes Drugs
Antidiabetes Drugs
In an animal study, an aqueous extract of collard leaves and stems has been shown to reduce glucose levels. Collard extract 60 mg/kg lowers blood glucose levels in a rat model of diabetes after both single- and multi-dose oral administration similarly to glibenclamide 5 mg/kg. Theoretically, collard extract might have additive effects when used concomitantly with antidiabetes drugs and may increase the risk of hypoglycemia. Monitor blood glucose levels closely. Dose adjustments may be necessary. Some antidiabetes drugs include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), and tolbutamide (Orinase).
Monograph
Collard: Uses, Safety & Side Effects
The bottom line
Collard is a leafy green vegetable in the cabbage family that is rich in vitamins, minerals, and fiber, and is best thought of as a nutritious food rather than a medicine. Eating it as part of a balanced diet is healthy for most people, but there is little high-quality research on collard as a concentrated supplement. If you take blood thinners or have kidney concerns, talk with your pharmacist or doctor because of its vitamin K and oxalate content.
- Scientific name
- Brassica oleracea var. viridis
- Family
- Brassicaceae
- Part used
- Leaves
- Common forms
- Fresh or cooked leaves, frozen greens; occasionally powders or capsules
People commonly use it for
- General nutrition and vitamin source
- Bone health
- Heart health support
- Digestive fiber
- Antioxidant intake
Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.
OverallLikely safe
Collard is widely eaten as a food and is generally safe for most people.
PregnancyInsufficient reliable information
Insufficient reliable information available; avoid amounts in excess of those found in foods.
Read the full pregnancy detailBreastfeedingInsufficient reliable information
Insufficient reliable information available; avoid amounts in excess of those found in foods.
Read the full breastfeeding detailPregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Overview
Collard (often called collard greens) is a leafy green vegetable in the cabbage and broccoli family. It comes from the plant Brassica oleracea, the same species that gives us kale, cabbage, and broccoli. Collard has large, smooth, dark-green leaves and is grown widely in warm and temperate regions, including the southern United States, where it is a popular food.
Most people use collard as a food rather than as a supplement. The leaves are usually cooked, steamed, sautéed, or added to soups and stews. Collard is valued for being rich in vitamins, minerals, and fiber while being low in calories.
How it works
Collard contains several compounds that may support health. It is high in fiber, which aids digestion and helps with regularity. It provides vitamin K, which is needed for blood clotting and bone health, and vitamin C and carotenoids that act as antioxidants.
Like other cabbage-family vegetables, collard contains glucosinolates, natural plant compounds that the body can convert into substances such as sulforaphane. Laboratory and animal studies suggest these compounds may have antioxidant and protective effects, but this research is early and does not prove that eating collard prevents or treats any disease in people.
Effectiveness
Does Collard work?
Evidence overview · 3 uses evaluated
3 Insufficient evidence
How to read these evidence grades
Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.
1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.
For Collard, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.
Also studied for 3 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Bladder cancer
Rating & evidence shown verbatim from Natural Medicines
Observational research has found that eating about 0.88 cups of cruciferous vegetables, such as cabbage, Brussels sprout, cauliflower, broccoli, kale, or collards, decreases the risk of developing bladder cancer by about 30% in men and women.
Sources
Ref 14864
Insufficient Reliable Evidence To Rate Breast cancer
Rating & evidence shown verbatim from Natural Medicines
Population research has found that higher intake of cruciferous vegetables, including broccoli, Brussels sprout, cabbage, cauliflower, collards, and kale, is associated with a slight increase in the risk of breast cancer in premenopausal women, while higher intake of cruciferous vegetables appears to be associated with a slight but statistically insignificant decrease in the risk of breast cancer in postmenopausal women.
Sources
Ref 26188
Insufficient Reliable Evidence To Rate Prostate cancer
Rating & evidence shown verbatim from Natural Medicines
Population research has found that people who consume higher amounts of green leafy vegetables, such as collard, spinach, mustard greens, and turnip greens, do not have a significantly lower risk of developing prostate cancer when compared with those who eat lower amounts.
Sources
Ref 25420
Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.
Safety & precautions
As a food, collard is safe for most people and is a healthy part of a balanced diet, including during pregnancy and breastfeeding. Wash the leaves well and cook them properly to reduce the risk of foodborne illness.
A few groups should be more careful. People taking blood-thinning medications should keep their intake of vitamin K–rich greens steady rather than suddenly eating much more or less, and should discuss this with their pharmacist or doctor. People with kidney stones or kidney disease may need to limit collard because it contains oxalates and potassium. Those with thyroid conditions should know that very large amounts of raw cabbage-family vegetables contain goitrogens, though normal cooked portions are not usually a concern.
Side effects
Collard is generally well tolerated. The most common complaints are gas, bloating, or stomach discomfort, especially when eaten in large amounts, because of its fiber and natural plant compounds.
Serious problems are uncommon. People prone to kidney stones may be affected by its oxalate content over time. As with any food, an allergic reaction is possible but rare. Concentrated supplement forms have not been well studied for safety, so it is best to get collard from food.
Dosing
There is no established medicinal dose for collard. As a food, it can be enjoyed in normal serving sizes as part of a varied diet, just like other vegetables.
If you choose a collard powder or capsule, there is no standardized dose, so follow the directions on the product label. Talk with your pharmacist or doctor before using concentrated supplements, especially if you take medications or have kidney or thyroid problems.
Pregnancy & Breastfeeding
Collard & Pregnancy
Collard & Breastfeeding
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.
© 2026 Therapeutic Research Center
© 2026 Therapeutic Research Center
Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center
References & further reading
The 4 references that drive our Collard monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.
- Zhao H, Lin J, Grossman HB, et al. Dietary isothiocyanates, GSTM1, GSTT1, NAT2 polymorphisms and bladder cancer risk. Int J Cancer 2007;120:2208-13.
- Cohen, J. H., Kristal, A. R., and Stanford, J. L. Fruit and vegetable intakes and prostate cancer risk. J Natl.Cancer Inst. 1-5-2000;92(1):61-68. PubMed
- Gaudet MM, Britton JA, Kabat GC, et al. Fruits, vegetables, and micronutrients in relation to breast cancer modified by menopause and hormone receptor status. Cancer Epidemiol Biomarkers Prev 2004;13(9):1485-94. DOI
- Amssayef A, Eddouks M. Antihyperglycemic Effect of the Moroccan Collard Green (Brassica oleracea var. viridis) in Streptozotocin-Induced Diabetic Rats. Endocr Metab Immune Disord Drug Targets 2020. PubMed
This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Brand directory
Brands that make products with Collard
91 brands in our database make a supplement containing Collard.
Advanced Nutrition by Zahler
135 products
Akasha Naturals
20 products
Applied Nutrition
76 products
Bare Performance Nutrition
12 products
Beast Sports Nutrition
23 products
Body Ecology
37 products
Catie's
23 products
Controlled Labs
29 products
Country Farms
76 products
Country Life
1,501 products
Country Life Realfood Organics
39 products
CTD Sports
1 product
Daily Nutrition
14 products
Designed by Dean
10 products
Designs for Health
295 products
Detox Organics
1 product
Divine Health
56 products
doTERRA
208 products
Douglas Laboratories
3,067 products
Dr. Berg
106 products
Dr. Berg's
16 products
Dr. Mercola
590 products
DrBerg Nutritionals
10 products
DrVita.com
1 product
Product directory
Supplement products with Collard
401 products in our database contain Collard. Open any to see its full ingredient list and every drug interaction we check.
Fermented Superfood Complex
by Swanson
View ingredients & interactions
Field of Greens
by Vibrant Health
View ingredients & interactions
Field of Greens
by Vibrant Health
View ingredients & interactions
Field Of Greens
by Vibrant Health
View ingredients & interactions
Field Of Greens
by Vibrant Health
View ingredients & interactions
Field Of Greens
by Vibrant Health
View ingredients & interactions
For Men
by Country Life Realfood Organics
View ingredients & interactions
For Men
by Country Life Realfood Organics
View ingredients & interactions
For Women
by Country Life Realfood Organics
View ingredients & interactions
For Women
by Country Life Realfood Organics
View ingredients & interactions
Fruit Superfood
by Terra Origin
View ingredients & interactions
Full Spectrum Reds & Greens
by INNOSUPPS
View ingredients & interactions
FulviMax
by Epigenetic Labs
View ingredients & interactions
Get Your Greens
by Happy Healthy Hippie
View ingredients & interactions
Gold Liquid Natural Tropical Berry Flavor
by NaturesPlus Source of Life Animal Parade
View ingredients & interactions
Gold Natural Cherry Flavor
by Natures Plus Source of Life Animal Parade
View ingredients & interactions
Green Superfood Powder Sweet Greens
by Nutrilite Organics
View ingredients & interactions
Green Surge Greens Powder Mixed Berry
by Jacked Factory
View ingredients & interactions
Green Surge Lemon Lime
by Jacked Factory JF
View ingredients & interactions
Green Surge Sour Apple
by Jacked Factory
View ingredients & interactions
Green Surge Sour Apple
by Jacked Factory JF
View ingredients & interactions
Green Surge Unflavored
by Jacked Factory JF
View ingredients & interactions
Greens Complete
by Akasha Naturals
View ingredients & interactions
Greens First
by Greens First
View ingredients & interactions
Pharmacist Counseling Corner
Collard: Common Questions
What is Collard used for, and does it work?
People use Collard for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Collard interact with prescription medications?
Yes. We list 86 medications with a known interaction with Collard. Use the checker above to see how Collard interacts with a specific drug.
How are Collard interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Collard with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Collard interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
Is Collard a medicine or a food?
Collard is best thought of as a nutritious vegetable, not a medicine. It provides vitamins, minerals, and fiber, but there is little research supporting it as a treatment for specific conditions.
Is it safe to eat Collard during pregnancy?
Yes, eating Collard in normal food amounts is generally safe and even beneficial during pregnancy because it provides folate, vitamins, and fiber. Wash and cook it well, and ask your doctor before using concentrated supplements.
Can Collard cause kidney stones?
Collard contains oxalates, which in large amounts may contribute to kidney stones in people who are prone to them. If you have a history of kidney stones, ask your doctor how much is appropriate for you.
Should I eat Collard raw or cooked?
Both are fine, but Collard is usually cooked, which makes the tough leaves easier to digest and may reduce the effect of natural goitrogens. Cooking also helps reduce the risk of foodborne germs.
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Keep exploring
Products that contain Collard
A rotating sample of real supplements in our database that list Collard — open any to see its full ingredients and every drug interaction we check.
- For Men by Country Life Realfood Organics
- Green Surge Lemon Lime by Jacked Factory JF
- Pure Greens by Zenith Labs
- Essential-4 Nutrition Pack by Douglas Laboratories
- PaleoGreens Mint Flavor by Designs for Health
- Greens First Chocolate by Greens First
- Doctor's Choice Multivitamin 45+ Women by Nature's Way
- Organic Superfood by Pure Synergy
- Six Daily Advanced Multivitamin by Nature's Lab
- Ultra Preventive by Douglas Laboratories
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