Drug & supplement interaction

Sea Buckthorn + Hydroxyurea

Hydroxyurea brand names: Droxia, Hydrea, Siklos, Xromi.

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 Sea Buckthorn and Hydroxyurea 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 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

Sea Buckthorn and Hydroxyurea

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 Hydroxyurea and Sea Buckthorn 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.

Sea Buckthorn safety at a glance

Sea Buckthorn overall Use caution Generally well tolerated as a food, but supplement safety has not been fully studied.

Pregnancy Use caution Food amounts are likely fine, but supplement doses are not well studied, so use caution and ask your doctor.

Breastfeeding Use caution Not enough reliable safety data on supplement use while breastfeeding; use caution.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Hydroxyurea and Sea Buckthorn? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Hydroxyurea

Interactions in our licensed database are recorded against drug classes, not just single drug names. Hydroxyurea is filed under 2 classifications — antineoplastics, oral drugs. Sea Buckthorn has documented interactions with 2 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate) and antihypertensive drugs (moderate) — and none of Hydroxyurea’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

Sea Buckthorn Does Interact With Other Medications

Sea Buckthorn has 289 moderate known drug interactions in our database — Hydroxyurea isn’t one of them. If you take anything else, check it against the full list below.

Moderate 289 No known interaction 2,541 (incl. Hydroxyurea)

Taking anything else?

Check Another of Your Medications Against Sea Buckthorn

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

What to actually watch for

No Interaction Found — But Data Suggests Sea Buckthorn and Hydroxyurea May Share a Side Effect

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.

A skin rash Additional detail
Sea Buckthorn
“Orally, high doses of sea buckthorn may cause yellow staining of the skin. One case of generalized yellow skin has been reported for a patient who consumed sea buckthorn 100 grams daily for 6 months. Topically, sea buckthorn oil has been associated with dryness, irritation, redness, and rash. Rash occurred in 4% of patients in one clinical study.”

Sea Buckthorn · Natural Medicines adverse-effect record, reported in pruritus.
4 sources cited

74072. Grad, S. C., Muresan, I., and Dumitrascu, D. L. Generalized yellow skin caused by high intake of sea buckthorn. Forsch.Komplementmed. 2012;19(3):153-156. PubMed

74077. Vlasov, V. V. [Hippophae oil in the treatment of superficial skin burns]. Vestn.Dermatol Venerol. 1970;44(6):69-72.

102845. Larmo P, Järvinen R, Laihia J, et al. Effects of a sea buckthorn oil spray emulsion on dry eye. Cont Lens Anterior Eye. 2019;42(4):428-433. PubMed

106089. De Seta F, Caruso S, Di Lorenzo G, Romano F, Mirandola M, Nappi RE. Efficacy and safety of a new vaginal gel for the treatment of symptoms associated with vulvovaginal atrophy in postmenopausal women: A double-blind randomized placebo-controlled study. Ma PubMed
Hydroxyurea

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

Reported for Sea Buckthorn but not commonly for Hydroxyurea: itching.

Effects for Hydroxyurea come from the ADVERSE REACTIONS section of its FDA label; effects for Sea Buckthorn come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 21,027 voluntary FDA FAERS reports for Hydroxyurea that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Overlapping uses

What Hydroxyurea Is Prescribed For, and What Sea Buckthorn Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Hydroxyurea is a prescription medicine with approved uses on its FDA label. Sea Buckthorn is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Hydroxyurea is prescribed for: Hydroxyurea is used for several serious conditions. Droxia, Siklos, and Xromi are each indicated to reduce the frequency of painful crises and reduce the need for blood transfusions in patients with sickle cell anemia who have recurrent moderate to severe painful crises. Siklos is approved for adults and children 2 years and older; Xromi is approved for children 6 months and older; Droxia is approved for adults. Hydrea capsules and Hydroxyurea capsules are indicated for resistant chronic myeloid leukemia and for locally advanced squamous cell carcinomas of the head and neck (excluding the lip) when used together with chemoradiation.

Sea Buckthorn has been studied for:

Cancer studied, not established Sea Buckthorn has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

Sea Buckthorn for cancer

Although there is interest in using oral sea buckthorn for reducing morbidity related to cancer and side effects related to chemotherapy, there is insufficient reliable information about the clinical effects of sea buckthorn for these uses.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Hydroxyurea on your own; if you are taking Sea Buckthorn for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Sea Buckthorn or Hydroxyurea

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Sea Buckthorn or Hydroxyurea, 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 Hydroxyurea

This page covers Sea Buckthorn only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydroxyurea page lists 18 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 10 minor.

From our pharmacist’s overview on the Hydroxyurea page

“People take hydroxyurea (Droxia, Hydrea, Siklos, Xromi) for serious reasons, most often sickle cell disease or certain blood cancers, and it only works if a steady dose reaches the bloodstream. That is exactly what nearly all 18 supplements listed here can undermine, so this page earns real vigilance rather than a skim.”

Reviewed by 2 · Jul 18, 2026

Open the Hydroxyurea interaction page

One more smart check

Taking Sea Buckthorn as Part of a Dietary Supplement Product? Check It for Interactions

We hold 253 real supplement products containing Sea Buckthorn, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sea Buckthorn. Even though Sea Buckthorn itself has no known interaction with Hydroxyurea, 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 Sea Buckthorn and Hydroxyurea 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 Sea Buckthorn

Top half

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

29 days ago today

Medication Hydroxyurea

Top 5%

#38 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 Sea Buckthorn reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Sea Buckthorn and Hydroxyurea records this page draws on were last updated July 10, 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 Sea Buckthorn

What is Sea Buckthorn?

Skin health and dryness
Dry eye symptoms
Digestive complaints
Heart and cholesterol support
General antioxidant and immune support

Sea buckthorn is a berry-bearing shrub rich in vitamins, carotenoids, and fatty acids that people use for skin, eye, digestive, and heart health. Early research is promising for a few uses like dry skin and dry eye, but most claims are not yet proven. It is generally well tolerated as a food, but talk to your pharmacist before using concentrated supplements.

Hippophae rhamnoides · Elaeagnaceae · Berries (fruit), seeds, seed and fruit oil, and sometimes leaves · Capsules, softgels, oil (seed or fruit), juice, powder, teas, topical creams and ointments

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

Sea Buckthorn: dosing

There is no official or standardized dose of sea buckthorn. The right amount depends on the product, its form (oil, capsule, juice, or powder), and how it is concentrated.The best approach is to follow the directions on the product label and not exceed the recommended amount.

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

Read the full Sea Buckthorn monograph & all interactions

Medication

About Hydroxyurea

What Is Hydroxyurea Used For?

Brand names: Droxia, Hydrea, Siklos, Xromi

Hydroxyurea is used for several serious conditions. Droxia, Siklos, and Xromi are each indicated to reduce the frequency of painful crises and reduce the need for blood transfusions in patients with sickle cell anemia who have recurrent moderate to severe painful crises. Siklos is approved for adults and children 2 years and older; Xromi is approved for children 6 months and older; Droxia is approved for adults.

Hydrea capsules and Hydroxyurea capsules are indicated for resistant chronic myeloid leukemia and for locally advanced squamous cell carcinomas of the head and neck (excluding the lip) when used together with chemoradiation.

Most-Reported Side Effects for Hydroxyurea

From FAERS, the FDA’s public side-effect reporting system (21,027 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 1,548 reports

Sickle cell anaemia with crisis 1,486 reports

Diarrhea 1,408 reports

Nausea 1,306 reports

Headache 1,068 reports

See full Hydroxyurea drug information

Keep checking

Other Drugs & Sea Buckthorn

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

0Major

289Moderate

0Minor

2,540No known interaction

289 Moderate 2,540 No interaction

Moderate

289 interactions

Showing 60 of 289 moderate interactions — see all 289 on the Sea Buckthorn page.

No interaction 2,540 drugs checked — show the list

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

Showing the 60 most looked-up of 2,540 medications checked with no known interaction — see the full Sea Buckthorn list.

See the full Sea Buckthorn interactions page

See every supplement checked against Hydroxyurea, ranked by severity

Evidence & sources

Sea Buckthorn References

The 7 references that drive our Sea Buckthorn 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.

Johansson AK, Korte H, Yang B, et al. Sea buckthorn berry oil inhibits platelet aggregation. J Nutr Biochem 2000;11:491-5.. PubMed
Grad, S. C., Muresan, I., and Dumitrascu, D. L. Generalized yellow skin caused by high intake of sea buckthorn. Forsch.Komplementmed. 2012;19(3):153-156. PubMed
Vlasov, V. V. [Hippophae oil in the treatment of superficial skin burns]. Vestn.Dermatol Venerol. 1970;44(6):69-72.
Chang BB, Wang F Xu TY Zhang QQ He J Zhang XJ Li J. Total flavones of Hippophae rhamnoides L. for essential hypertension: a systematic review of randomized controlled trials. Chinese Journal of Evidence-Based Medicine. 2009;9(11):1207-1213. DOI
Olas B, Kontek B, Szczesna M, et al. Inhibition of blood platelet adhesion by phenolics rich fraction of Hippophae rhamnoides L. fruits. J Physiol Pharmacol. 2017;68(2):223-9.
Larmo P, Järvinen R, Laihia J, et al. Effects of a sea buckthorn oil spray emulsion on dry eye. Cont Lens Anterior Eye. 2019;42(4):428-433. PubMed
De Seta F, Caruso S, Di Lorenzo G, Romano F, Mirandola M, Nappi RE. Efficacy and safety of a new vaginal gel for the treatment of symptoms associated with vulvovaginal atrophy in postmenopausal women: A double-blind randomized placebo-controlled study. Ma 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.

Pharmacist Counseling Corner

Taking Sea Buckthorn and Hydroxyurea Together: Common Questions

Is it safe to take Sea Buckthorn with Hydroxyurea?

We do not list a known interaction between Sea Buckthorn and Hydroxyurea. 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 Sea Buckthorn and Hydroxyurea have any of the same side effects?

Yes — our sources link each of them separately to one 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.

Are Sea Buckthorn and Hydroxyurea used for the same thing?

They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Sea Buckthorn in each. That is a conversation for your prescriber, especially if Hydroxyurea is being adjusted to a target.

How was the Sea Buckthorn and Hydroxyurea combination checked?

Interactions in our licensed database are recorded against drug classes. Hydroxyurea is filed under 2 classifications, and Sea Buckthorn has documented interactions with 2 drug classes — none of Hydroxyurea'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 Sea Buckthorn interact with any other medications?

Yes. Sea Buckthorn has 289 documented drug interactions in our database — Hydroxyurea 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 Hydroxyurea interact with any supplements?

Yes. Hydroxyurea has documented interactions with 18 supplements in our database — Sea Buckthorn is not one of them. The Hydroxyurea 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

Sea Buckthorn monograph Uses, safety profile, and every drug interaction in one place Hydroxyurea drug information The full plain-English guide to this medication Hydroxyurea supplement interactions Every supplement checked against Hydroxyurea, 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 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Hydroxyurea and Sea Buckthorn?

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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.