Drug & supplement interaction

Black Seed + Cefaclor

Cefaclor brand names: Ceclor CD, Ceclor.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Black Seed and Cefaclor in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Cefaclor states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Black Seed and Cefaclor

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Cefaclor and Black Seed in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Black Seed safety at a glance

Black Seed overall Use caution Likely safe in food amounts, but higher supplement doses are less studied long-term.

Pregnancy Likely Unsafe When used orally in amounts exceeding those found in food. Black seed may decrease or inhibit uterine contractions and may have contraceptive activity. Read the full pregnancy detail

Breastfeeding Use caution Not enough reliable safety information, so it is best to avoid supplement doses.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Cefaclor and Black Seed? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Cefaclor

Interactions in our licensed database are recorded against drug classes, not just single drug names. Cefaclor is filed under 6 classifications — including organic anion transporter 3 (oat3) substrates, organic anion transporter 1 (oat1) substrates, antibiotic drugs. Black Seed has documented interactions with 14 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), antidiabetes drugs (moderate) and antihypertensive drugs (moderate) — and none of Cefaclor’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Black Seed Does Interact With Other Medications

Black Seed has 912 moderate known drug interactions in our database — Cefaclor isn’t one of them. If you take anything else, check it against the full list below.

Moderate 912 No known interaction 1,918 (incl. Cefaclor)

Taking anything else?

Check Another of Your Medications Against Black Seed

Covers the 2,830 medications we’ve checked against Black Seed. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Black Seed and Cefaclor May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

A severe skin reaction Worth acting on Additional detail
Black Seed
“Orally, black seed can cause itching, but this adverse effect is rare. It has also been reported to cause bullous drug eruption and maculopapular eruption. Topically, black seed and its oil have been reported to cause allergic contact dermatitis. Rarely, topical use of the oil has been reported to cause a rash related to drug reaction with eosinophilia and systemic symptoms (DRESS).”

Black Seed · Natural Medicines adverse-effect record, reported in dermatitis.
6 sources cited

94481. Farhangi MA, Dehghan P, Tajmiri S, Abbasi MM. The effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) - 1, Nesfatin-1 and anthropometric features in patients with Hashimoto's thyroiditis: a randomized controlled

94480. Bonhomme A, Poreaux C, Jouen F, et al. Bullous drug eruption to Nigella sativa oil: Consideration of the use of a herbal medicine - clinical report and review of the literature. J Eur Acad Dermatol Venereol 2017;31:e217-e219.

100324. Dehavay F, Kolivras A, Scheers C. Local and systemic adverse skin reactions following the use of herbal products believed to contain Nigella sativa seeds and oil. Contact Dermatitis. 2019 Mar;80(3):176-177.

36053. Ali, B. H. and Blunden, G. Pharmacological and toxicological properties of Nigella sativa. Phytother.Res. 2003;17(4):299-305.

36296. al Sheikh, O. A. and Gad el-Rab, M. O. Allergic contact dermatitis: clinical features and profile of sensitizing allergens in Riyadh, Saudi Arabia. Int J Dermatol. 1996;35(7):493-497.

36297. Steinmann, A., Schatzle, M., Agathos, M., and Breit, R. Allergic contact dermatitis from black cumin (Nigella sativa) oil after topical use. Contact Dermatitis 1997;36(5):268-269.
“Orally, black seed has been reported to cause bullous drug eruption and maculopapular eruption. Topically, black seed and its oil can cause allergic contact dermatitis (6,36053,36296,36297,100324,110266). One case of bullous drug eruption with skin detachment has been reported for a 54-year-old woman who used black seed oil orally. The eruptions resolved following treatment with clobetasol propionate 0.05%.”

Black Seed · Natural Medicines adverse-effect record, reported in dermatitis.
6 sources cited

94480. Bonhomme A, Poreaux C, Jouen F, et al. Bullous drug eruption to Nigella sativa oil: Consideration of the use of a herbal medicine - clinical report and review of the literature. J Eur Acad Dermatol Venereol 2017;31:e217-e219.

100324. Dehavay F, Kolivras A, Scheers C. Local and systemic adverse skin reactions following the use of herbal products believed to contain Nigella sativa seeds and oil. Contact Dermatitis. 2019 Mar;80(3):176-177.

6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.

36053. Ali, B. H. and Blunden, G. Pharmacological and toxicological properties of Nigella sativa. Phytother.Res. 2003;17(4):299-305.

36296. al Sheikh, O. A. and Gad el-Rab, M. O. Allergic contact dermatitis: clinical features and profile of sensitizing allergens in Riyadh, Saudi Arabia. Int J Dermatol. 1996;35(7):493-497.

36297. Steinmann, A., Schatzle, M., Agathos, M., and Breit, R. Allergic contact dermatitis from black cumin (Nigella sativa) oil after topical use. Contact Dermatitis 1997;36(5):268-269.
Cefaclor

Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›
Kidney problems Worth acting on Additional detail
Black Seed
“Orally, black seed might cause renal dysfunction. A case of acute renal failure thought to be related to use of black seed tablets 2-2.5 grams daily has been reported for a 62 year-old patient with diabetes. Additionally, a case of acute kidney injury, rhabdomyolysis, and hepatotoxicity has been reported in an otherwise healthy 26-year-old male after taking black seed oil 1000 mg twice daily for 1 month.”

Black Seed · Natural Medicines adverse-effect record, reported in diabetes.
2 sources cited

94477. Arslan E, Sayin S, Demirbas S, et al. A case study report of acute renal failure associated with Nigella sativa in a diabetic patient. J Integr Med 2013;11:64-6. PubMed

114812. Sener K, Cakir A, Yesiloglu O, Altug E, Guven R, Korkut S. Rhabdomyolysis and acute kidney injury after consumption of black seed oil. Toxicon 2024;245:107787. PubMed
“While intake of black seed has been associated with hepatotoxicity in some animal research, other animal research has not confirmed this finding. One case report describes hepatotoxicity, kidney injury, and rhabdomyolysis occurring in an otherwise healthy 26-year-old male after taking black seed oil 1000 mg twice daily for 1 month. The patient was hospitalized for critical care management, including hemodialysis.”

Black Seed · Natural Medicines adverse-effect record, reported in muscle breakdown.
3 sources cited

245. Tennekoon KH, Jeevathayaparan S, Kurukulasooriya AP, Karunanayake EH. Possible hepatotoxicity of Nigella sativa seeds and Dregea volubilis leaves. J Ethnopharmacol 1991;31:283-9. PubMed

95982. Muneera KE, Majeed A, Naveed AK. Comparative evaluation of nigella sativa (Kalonji) and simvastatin for the treatment of hyperlipidemia and in the induction of hepatotoxicity. Pak J Pharm Sci. 2015 Mar;28(2):493-8.

114812. Sener K, Cakir A, Yesiloglu O, Altug E, Guven R, Korkut S. Rhabdomyolysis and acute kidney injury after consumption of black seed oil. Toxicon 2024;245:107787. PubMed
Cefaclor

Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›
Bloating or gas / Stomach upset / Diarrhea Additional detail
Black Seed
“In a clinical trial, unspecified gastrointestinal complaints occurred in 20% of patients taking black seed oil orally. Gastrointestinal complaints occurred rarely in another clinical trial; however, one patient in this study was hospitalized for nausea and vomiting thought to be associated with black seed oil.”

Black Seed · Natural Medicines adverse-effect record, reported in constipation.
6 sources cited

36071. Kalus, U., Pruss, A., Bystron, J., Jurecka, M., Smekalova, A., Lichius, J. J., and Kiesewetter, H. Effect of Nigella sativa (black seed) on subjective feeling in patients with allergic diseases. Phytother.Res. 2003;17(10):1209-1214.

110267. Koshak AE, Koshak EA, Mobeireek AF, et al. Nigella sativa for the treatment of COVID-19: An open-label randomized controlled clinical trial. Complement Ther Med 2021;61:102769. PubMed

36180. Akhondian, J., Parsa, A., and Rakhshande, H. The effect of Nigella sativa L. (black cumin seed) on intractable pediatric seizures. Med Sci Monit. 2007;13(12):CR555-CR559.

94487. Mohtashami R, Huseini HF, Heydari M, et al. Efficacy and safety of honey based formulation of Nigella sativa seed oil in functional dyspepsia: A double blind randomized controlled clinical trial. J Ethnopharmacol 2015;175:147-52. PubMed

94479. Bamosa AO, Kaatabi H, Lebdaa FM, et al. Effect of Nigella sativa seeds on the glycemic control of patients with type 2 diabetes mellitus. Indian J Physiol Pharmacol 2010;54:344-54.

94491. Shawki M, El Wakeel L, Shatla R, et al. The clinical outcome of adjuvant therapy with black seed oil on intractable paediatric seizures: a pilot study. Epileptic Disord 2013;15:295-301. PubMed
Cefaclor

Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›
Constipation / Vomiting / Nausea Additional detail

Black Seed

“Orally and topically, black seed seems to be well tolerated.

Most Common Adverse Effects:

Orally: Constipation, gastric burning or discomfort, nausea, and vomiting.”

Black Seed · Natural Medicines adverse-effect record, reported in constipation.

Cefaclor

Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›
Itching Additional detail

Black Seed

Recorded for Black Seed in the same Natural Medicines adverse-effect record shown under A severe skin reaction above.

Cefaclor

Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›
A skin rash Additional detail

Black Seed

Recorded for Black Seed in the same Natural Medicines adverse-effect record shown under A severe skin reaction above.

Cefaclor

Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›

Reported for Black Seed but not commonly for Cefaclor: liver problems, severe muscle breakdown and bleeding or bruising.

Effects for Cefaclor come from the ADVERSE REACTIONS section of its FDA label; effects for Black Seed come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Black Seed in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally in amounts exceeding those found in food. Black seed may decrease or inhibit uterine contractions and may have contraceptive activity.

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

How to take them

Some Cefaclor Products Have a Food Rule — Black Seed Should Not Break It

At least one FDA label for a product containing Cefaclor says to take it with food. If you take Black Seed on an empty stomach out of habit, keep them separate — and take Cefaclor with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Cefaclor products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

DOSAGE AND ADMINISTRATION The absorption of cefaclor extended-release tablets is enhanced when it is administered with food.

From the Dosage and Administration section of the FDA label we read for Cefaclor — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Black Seed or Cefaclor

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Black Seed or Cefaclor, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Cefaclor

This page covers Black Seed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cefaclor page lists 60 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Siberian Cocklebur (major), African Wild Potato (moderate) and Aristolochia (moderate).

By severity: 3 major · 46 moderate · 11 minor.

From our pharmacist’s overview on the Cefaclor page

“The entries worth understanding before any others on this cefaclor (Ceclor) page are the kidney risks and charcoal. Cefaclor is a cephalosporin antibiotic, typically a short course for ear, sinus, throat, or skin infections, and two herbs here, Siberian cocklebur and asarabacca, can damage the kidneys on their own, so pairing either wi…”

Reviewed by 2 · Jul 18, 2026

Open the Cefaclor interaction page

One more smart check

Taking Black Seed as Part of a Dietary Supplement Product? Check It for Interactions

We hold 226 real supplement products containing Black Seed, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Seed. Even though Black Seed itself has no known interaction with Cefaclor, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Black Seed and Cefaclor Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Black Seed

Top 25%

#197 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Cefaclor

Top 10%

#221 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Black Seed reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Black Seed and Cefaclor records this page draws on were last updated July 11, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Black Seed

What is Black Seed?

Respiratory support (asthma, allergies, cough)
Digestive upset
Immune support
Blood sugar and cholesterol support
General inflammation

Black seed (Nigella sativa) is a traditional spice and remedy that has been studied for asthma, blood sugar, cholesterol, and blood pressure, with early research showing some promise but no firmly proven benefits. It is generally well tolerated in food amounts, but supplement-strength doses are less studied, so talk to your pharmacist or doctor before using it—especially if you are pregnant, breastfeeding, or take other medicines.

Nigella sativa · Ranunculaceae · Seeds and the oil pressed from the seeds · Whole seeds, ground powder, capsules, softgels, and cold-pressed oil

An interaction check asks whether these two react with each other — it does not ask whether Black Seed is a good idea for someone in your situation. Here is what our Black Seed record says about it on its own.

Black Seed: dosing

There is no official, standardized dose for black seed. Studies have used a wide range of amounts of seed powder or oil, and products vary a lot in strength.The safest approach is to follow the directions on the product label and start with the lowest suggested amount.

From our Black Seed monograph — the full record covers uses, side effects and every documented interaction.

Read the full Black Seed monograph & all interactions

Medication

About Cefaclor

What Is Cefaclor Used For?

Brand names: Ceclor CD, Ceclor

Cefaclor treats a range of bacterial infections. Cefaclor capsules and oral suspension are used for ear infections (otitis media), lower respiratory tract infections including pneumonia, strep throat and tonsillitis, urinary tract infections (including kidney infections and bladder infections), and skin and skin structure infections.

Cefaclor extended-release tablets are approved for a narrower set of uses in adults: acute bacterial flare-ups of chronic bronchitis, strep throat and tonsillitis, and uncomplicated skin and skin structure infections. Not all formulations are approved for the same conditions, so the form matters.

See full Cefaclor drug information

Keep checking

Other Drugs & Black Seed

Browse every other medication we’ve checked against Black Seed — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major

912Moderate

0Minor

1,917No known interaction

912 Moderate 1,917 No interaction

Moderate

912 interactions

Showing 60 of 912 moderate interactions — see all 912 on the Black Seed page.

No interaction 1,917 drugs checked — show the list

We also checked Black Seed against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,917 medications checked with no known interaction — see the full Black Seed list.

See the full Black Seed interactions page

See every supplement checked against Cefaclor, ranked by severity

Evidence & sources

Black Seed References

The 60 references that drive our Black Seed 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.

The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
Aqel M, Shaheen R. Effects of the volatile oil of black seed seeds on the uterine smooth muscle of rat and guinea pig. J Ethnopharmacol 1996;52:23-6.
Keshri G, Singh MM, Lakshmi V, Kamboj VP. Post-coital contraceptive efficacy of the seeds of Black seed in rats. Indian J Physiol Pharmacol 1995;39:59-62.
Tennekoon KH, Jeevathayaparan S, Kurukulasooriya AP, Karunanayake EH. Possible hepatotoxicity of Nigella sativa seeds and Dregea volubilis leaves. J Ethnopharmacol 1991;31:283-9. PubMed
Dehkordi FR, Kamkhah AF. Antihypertensive effect of Nigella sativa seed extract in patients with mild hypertension. Fundam Clin Pharmacol 2008;22:447-52.
Zaoui, A., Cherrah, Y., Lacaille-Dubois, M. A., Settaf, A., Amarouch, H., and Hassar, M. [Diuretic and hypotensive effects of Nigella sativa in the spontaneously hypertensive rat]. Therapie 2000;55(3):379-382.
Enomoto, S., Asano, R., Iwahori, Y., Narui, T., Okada, Y., Singab, A. N., and Okuyama, T. Hematological studies on black cumin oil from the seeds of Nigella sativa L. Biol.Pharm.Bull 2001;24(3):307-310. PubMed
Meral, I., Yener, Z., Kahraman, T., and Mert, N. Effect of Nigella sativa on glucose concentration, lipid peroxidation, anti-oxidant defence system and liver damage in experimentally-induced diabetic rabbits. J Vet.Med A Physiol Pathol.Clin Med 2001;48(1
Al Jishi, S. A. and Abuo, Hozaifa B. Effect of Nigella sativa on blood hemostatic function in rats. J Ethnopharmacol. 2003;85(1):7-14. PubMed
Ali, B. H. and Blunden, G. Pharmacological and toxicological properties of Nigella sativa. Phytother.Res. 2003;17(4):299-305.
Al Naggar, T. B., Gomez-Serranillos, M. P., Carretero, M. E., and Villar, A. M. Neuropharmacological activity of Nigella sativa L. extracts. J Ethnopharmacol. 2003;88(1):63-68. PubMed
Kalus, U., Pruss, A., Bystron, J., Jurecka, M., Smekalova, A., Lichius, J. J., and Kiesewetter, H. Effect of Nigella sativa (black seed) on subjective feeling in patients with allergic diseases. Phytother.Res. 2003;17(10):1209-1214.
Islam, S. N., Begum, P., Ahsan, T., Huque, S., and Ahsan, M. Immunosuppressive and cytotoxic properties of Nigella sativa. Phytother.Res. 2004;18(5):395-398.
Fararh, K. M., Atoji, Y., Shimizu, Y., Shiina, T., Nikami, H., and Takewaki, T. Mechanisms of the hypoglycaemic and immunopotentiating effects of Nigella sativa L. oil in streptozotocin-induced diabetic hamsters. Res Vet.Sci 2004;77(2):123-129. PubMed
Awad, E. M. and Binder, B. R. In vitro induction of endothelial cell fibrinolytic alterations by Nigella sativa. Phytomedicine 2005;12(3):194-202. PubMed
El Obeid, A., Al Harbi, S., Al Jomah, N., and Hassib, A. Herbal melanin modulates tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6) and vascular endothelial growth factor (VEGF) production. Phytomedicine. 2006;13(5):324-333.
Abbas, A. T., Abdel-Aziz, M. M., Zalata, K. R., and Tel, Abd Al-Galel. Effect of dexamethasone and Nigella sativa on peripheral blood eosinophil count, IgG1 and IgG2a, cytokine profiles and lung inflammation in murine model of allergic asthma. Egypt J Im
Kaleem, M., Kirmani, D., Asif, M., Ahmed, Q., and Bano, B. Biochemical effects of Nigella sativa L seeds in diabetic rats. Indian J Exp.Biol. 2006;44(9):745-748.
Hawsawi, Z. A., Ali, B. A., and Bamosa, A. O. Effect of Nigella sativa (Black Seed) and thymoquinone on blood glucose in albino rats. Ann.Saudi Med 2001;21(3-4):242-244.
Massadeh, A. M., Al Safi, S. A., Momani, I. F., Al Mahmoud, M., and Alkofahi, A. S. Analysis of cadmium and lead in mice organs: effect of Nigella sativa L. (Black Cumin) on the distribution and immunosuppressive effect of cadmium-lead mixture in mice. B PubMed
Akhondian, J., Parsa, A., and Rakhshande, H. The effect of Nigella sativa L. (black cumin seed) on intractable pediatric seizures. Med Sci Monit. 2007;13(12):CR555-CR559.
Meddah, B., Ducroc, R., El Abbes, Faouzi M., Eto, B., Mahraoui, L., Benhaddou-Andaloussi, A., Martineau, L. C., Cherrah, Y., and Haddad, P. S. Nigella sativa inhibits intestinal glucose absorption and improves glucose tolerance in rats. J Ethnopharmacol. PubMed
Najmi, A., Nasiruddin, M., Khan, R. A., and Haque, S. F. Effect of Nigella sativa oil on various clinical and biochemical parameters of insulin resistance syndrome. Int J Diabetes Dev.Ctries. 2008;28(1):11-14.
al Sheikh, O. A. and Gad el-Rab, M. O. Allergic contact dermatitis: clinical features and profile of sensitizing allergens in Riyadh, Saudi Arabia. Int J Dermatol. 1996;35(7):493-497.
Steinmann, A., Schatzle, M., Agathos, M., and Breit, R. Allergic contact dermatitis from black cumin (Nigella sativa) oil after topical use. Contact Dermatitis 1997;36(5):268-269.
Al-Jenoobi FI, Al-Suwayeh SA, Muzaffar I, et al. Effects of Nigella sativa and Lepidium sativum on cyclosporine pharmacokinetics. Biomed Res Int 2013;2013:953520.
Arslan E, Sayin S, Demirbas S, et al. A case study report of acute renal failure associated with Nigella sativa in a diabetic patient. J Integr Med 2013;11:64-6. PubMed
Bamosa AO, Kaatabi H, Lebdaa FM, et al. Effect of Nigella sativa seeds on the glycemic control of patients with type 2 diabetes mellitus. Indian J Physiol Pharmacol 2010;54:344-54.
Bonhomme A, Poreaux C, Jouen F, et al. Bullous drug eruption to Nigella sativa oil: Consideration of the use of a herbal medicine - clinical report and review of the literature. J Eur Acad Dermatol Venereol 2017;31:e217-e219.
Farhangi MA, Dehghan P, Tajmiri S, Abbasi MM. The effects of Nigella sativa on thyroid function, serum Vascular Endothelial Growth Factor (VEGF) - 1, Nesfatin-1 and anthropometric features in patients with Hashimoto's thyroiditis: a randomized controlled
Kaatabi H, Bamosa AO, Badar A, et al. Nigella sativa improves glycemic control and ameliorates oxidative stress in patients with type 2 diabetes mellitus: placebo controlled participant blinded clinical trial. PLoS One 2015;10:e0113486. PubMed
Mohtashami R, Huseini HF, Heydari M, et al. Efficacy and safety of honey based formulation of Nigella sativa seed oil in functional dyspepsia: A double blind randomized controlled clinical trial. J Ethnopharmacol 2015;175:147-52. PubMed
Perveen T, Haider S, Zuberi NA, et al. Increased 5-HT levels following repeated administration of Nigella sativa L. (Black Seed) oil produce antidepressant effects in rats. Sci Pharm 2013;82:161-70. PubMed
Sahebkar A, Soranna D, Liu X, et al. A systematic review and meta-analysis of randomized controlled trials investigating the effects of supplementation with Nigella sativa (black seed) on blood pressure. J Hypertens 2016;34:2127-35. PubMed
Shawki M, El Wakeel L, Shatla R, et al. The clinical outcome of adjuvant therapy with black seed oil on intractable paediatric seizures: a pilot study. Epileptic Disord 2013;15:295-301. PubMed
Muneera KE, Majeed A, Naveed AK. Comparative evaluation of nigella sativa (Kalonji) and simvastatin for the treatment of hyperlipidemia and in the induction of hepatotoxicity. Pak J Pharm Sci. 2015 Mar;28(2):493-8.
Mahdavi R, Namazi N, Alizadeh M, Farajnia S. Effects of Nigella sativa oil with a low-calorie diet on cardiometabolic risk factors in obese women: a randomized controlled clinical trial. Food Funct. 2015;6(6):2041-8. PubMed
Fallah Huseini H, Amini M, Mohtashami R, et al. Blood pressure lowering effect of Nigella sativa L. seed oil in healthy volunteers: a randomized, double-blind, placebo-controlled clinical trial. Phytother Res. 2013;27(12):1849-53.
Dehavay F, Kolivras A, Scheers C. Local and systemic adverse skin reactions following the use of herbal products believed to contain Nigella sativa seeds and oil. Contact Dermatitis. 2019 Mar;80(3):176-177.
Kooshki A, Tofighiyan T, Rastgoo N, Rakhshani MH, Miri M. Effect of Nigella sativa oil supplement on risk factors for cardiovascular diseases in patients with type 2 diabetes mellitus. Phytother Res. 2020.
Warner ME, Warner PA, Sprung J, Warner MA. Black seed oil and perioperative serotonin syndrome: A case report. A A Pract. 2019;13(11):420-422. PubMed
Alam MA, Bin Jardan YA, Raish M, Al-Mohizea AM, Ahad A, Al-Jenoobi FBI. Effect of Nigella sativa and fenugreek on the pharmacokinetics and pharmacodynamics of amlodipine in hypertensive rats. Curr Drug Metab. 2020;21(4):318-325. PubMed
Moustafa HAM, El Wakeel LM, Halawa MR, Sabri NA, El-Bahy AZ, Singab AN. Effect of Nigella sativa oil versus metformin on glycemic control and biochemical parameters of newly diagnosed type 2 diabetes mellitus patients. Endocrine 2019;65(2):286-94. PubMed
Safi S, Razmpoosh E, Fallahzadeh H, et al. The effect of Nigella sativa on appetite, anthropometric and body composition indices among overweight and obese women: A crossover, double-blind, placebo-controlled, randomized clinical trial. Complement Ther Me PubMed
Wang X, Jiang A, Batra V. Severe thrombocytopenia associated with black seed oil and evening primrose oil. Cureus. 2020;12(6):e8390. PubMed
Alkharfy K, Jan B, Alotaibi K, et al. Clopidogrel-herb Interactions: A Pharmacokinetic and Pharmacodynamic Assessment in a Rat Model. Curr Drug Metab 2021;22(12):969-977. PubMed
Bin Jardan YA, Ahad A, Raish M, Alam MA, Al-Mohizea AM, Al-Jenoobi FI. Effects of garden cress, fenugreek and black seed on the pharmacodynamics of metoprolol: an herb-drug interaction study in rats with hypertension. Pharm Biol 2021;59(1):1088-1097. PubMed
Thomas JV, Mohan ME, Prabhakaran P, Das S S, Maliakel B, I M K. A phase I clinical trial to evaluate the safety of thymoquinone-rich black cumin oil (BlaQmax®) on healthy subjects: Randomized, double-blinded, placebo-controlled prospective study. Toxicol PubMed
Assier H, Kouby F, Ingen-Housz-Oro S, Roux C. Severe allergic contact connubial dermatitis to Nigella Sativa Seed Oil due to repeated contacts to beard cosmetics. Contact Dermatitis 2022. PubMed
Koshak AE, Koshak EA, Mobeireek AF, et al. Nigella sativa for the treatment of COVID-19: An open-label randomized controlled clinical trial. Complement Ther Med 2021;61:102769. PubMed
Hadi S, Daryabeygi-Khotbehsara R, Mirmiran P, et al. Effect of Nigella sativa oil extract on cardiometabolic risk factors in type 2 diabetes: A randomized, double-blind, placebo-controlled clinical trial. Phytother Res 2021;35(7):3747-3755.
Ali SM, Chen P, Sheikh S, et al. Thymoquinone with metformin decreases fasting, post prandial glucose, and HbA1c in type 2 diabetic patients. Drug Res (Stuttg) 2021;71(6):302-306. PubMed
Tavakoli-Rouzbehani OM, Abbasnezhad M, Kheirouri S, Alizadeh M. Effects of Nigella sativa oil supplementation on selected metabolic parameters and anthropometric indices in patients with coronary artery disease: A randomized, double-blind, placebo-control
Fargeas M, Calugareanu A, Ben-Said B. Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome after topical use of Nigella sativa (black cumin) oil. Contact Dermatitis 2022;87(2):203-204.
Wang Z, Wang Z, Wang X, et al. Potential food-drug interaction risk of thymoquinone with warfarin. Chem Biol Interact. 2022;365:110070. PubMed
Wang Z, Wang X, Wang Z, et al. Potential herb-drug interaction risk of thymoquinone and phenytoin. Chem Biol Interact. 2022;353:109801. PubMed
Al-Mohizea AM, Ahad A, El-Maghraby GM, et al. Effects of Nigella sativa, Lepidium sativum and Trigonella foenum-graecum on sildenafil disposition in beagle dogs. Eur J Drug Metab Pharmacokinet. 2015;40(2):219-24. PubMed
Alkharfy KM, Al-Jenoobi FI, Al-Mohizea AM, et al. Effects of Lepidium sativum, Nigella sativa and Trigonella foenum-graceum on phenytoin pharmacokinetics in beagle dogs. Phytother Res. 2013;27(12):1800-4.
Abutaima R, Al-Ebini Y, Alkofahi A, et al. In vivo assessment of black seed oil single dose on prednisolone pharmacokinetics. J Pharm Pharmacol 2024;76(1):57-63.
Sener K, Cakir A, Yesiloglu O, Altug E, Guven R, Korkut S. Rhabdomyolysis and acute kidney injury after consumption of black seed oil. Toxicon 2024;245:107787. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Related: nutrient depletion

Cefaclor Is Linked to Lower Levels of 7 Nutrients

Natural Medicines records Cefaclor as a medicine that can lower these. This is not an interaction with Black Seed — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:

Read the full Cefaclor nutrient depletion report ›

Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.

Pharmacist Counseling Corner

Taking Black Seed and Cefaclor Together: Common Questions

Is it safe to take Black Seed with Cefaclor?

We do not list a known interaction between Black Seed and Cefaclor. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Do Black Seed and Cefaclor have any of the same side effects?

Yes — our sources link each of them separately to 10 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.

Should I take Black Seed and Cefaclor at the same time of day?

At least one FDA label for a product containing Cefaclor says to take it with food. If you take Black Seed on an empty stomach out of habit, keep them separate and take Cefaclor with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Cefaclor products can differ — so check the directions on your own box. This is about absorption, not an interaction.

How was the Black Seed and Cefaclor combination checked?

Interactions in our licensed database are recorded against drug classes. Cefaclor is filed under 6 classifications, and Black Seed has documented interactions with 14 drug classes — none of Cefaclor's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Black Seed interact with any other medications?

Yes. Black Seed has 912 documented drug interactions in our database — Cefaclor is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Cefaclor interact with any supplements?

Yes. Cefaclor has documented interactions with 60 supplements in our database — Black Seed is not one of them. The Cefaclor interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Black Seed monograph Uses, safety profile, and every drug interaction in one place Cefaclor drug information The full plain-English guide to this medication Cefaclor supplement interactions Every supplement checked against Cefaclor, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 60 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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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.