Drug & supplement interaction

Lychee + Promethazine

Promethazine brand name: Phenergan.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Lychee and Promethazine 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

Lychee and Promethazine

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 Promethazine and Lychee 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.

Lychee safety at a glance

Lychee overall Use caution The fruit is generally safe as food, but concentrated extracts are not well studied and unripe fruit carries specific risks.
Pregnancy Use caution Eating lychee fruit in normal food amounts is likely fine, but concentrated extracts have not been studied and should be avoided.
Breastfeeding Use caution Lychee as a food is likely fine, but there is not enough safety data on extracts during breastfeeding.

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

Still wondering about combining Promethazine and Lychee? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Promethazine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Promethazine is filed under 4 classifications — including phenothiazines, anticholinergic drugs, photosensitizing drugs. Lychee has documented interactions with 2 drug classes — the most serious being antidiabetes drugs (moderate) and immunosuppressants (minor) — and none of Promethazine’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

Lychee Does Interact With Other Medications

Lychee has 86 moderate, 121 minor known drug interactions in our database — Promethazine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 86 Minor 121 No known interaction 2,623 (incl. Promethazine)
Taking anything else?

Check Another of Your Medications Against Lychee

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

What to actually watch for

No Interaction Found — But Data Suggests Lychee and Promethazine 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.

  • Seizures Worth acting on Additional detail

    Lychee

    “Orally, lychee has been linked to hypoglycemic encephalopathy. A 20-year retrospective review of cases from India, Vietnam, and Bangladesh found an association between lychee consumption and increased risk of acute hypoglycemic encephalopathy in children, especially in those who were malnourished. They presented with seizures and other neurological symptoms and had a high mortality rate.”

    Lychee · Natural Medicines adverse-effect record, reported in epilepsy.

    6 sources cited
    1. 96609. John TJ, Das M. Outbreaks of Hypoglycemic Encephalopathy in Muzaffarpur, India: Are These Caused by Toxins in Litchi Fruit?: The Point. Indian Pediatr. 2016;53(5):399.
    2. 96610. John TJ. Exploration of Association between Litchi Consumption and Seasonal Acute Encephalopathy Syndrome: Pediatric Infectious Disease Specialist's Viewpoint. Indian Pediatr. 2017;54(4):323-325. DOI
    3. 96612. Shrivastava A, Kumar A, Thomas JD, et al. Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study. Lancet Glob Health. 2017;5(4):e458-e466.
    4. 96613. Spencer PS, Palmer VS, Mazumder R. Probable toxic cause for suspected lychee-linked viral encephalitis. Emerg Infect Dis. 2015;21(5):904-5. DOI
    5. 96611. Mathew JL. Exploration of Association between Litchi Consumption and Seasonal Acute Encephalopathy Syndrome: Evidence-based Medicine Viewpoint. Indian Pediatr. 2017;54(4):319-323. PubMed
    6. 96615. Vashishtha VM. Outbreaks of Hypoglycemic Encephalopathy in Muzaffarpur, India: Are These Caused by Toxins in Litchi Fruit?: The Counterpoint. Indian Pediatr. 2016 May 8;53(5):399-402.

    Promethazine

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

  • Hives Worth acting on Additional detail

    Lychee

    “Orally, lychee can cause allergic reactions such as urticaria, dermatitis, tongue and lip swelling, shortness of breath, and anaphylaxis.

    Topically, contact with lychee fruit can cause allergic contact dermatitis.”

    Lychee · Natural Medicines adverse-effect record, reported in dermatitis.

    4 sources cited
    1. 26955. Niggemann B, Reibel S, Hipler C, Wahn U. Anaphylactic reaction to lychee in a 12-year-old girl: cross-reactivity to latex? Pediatr Allergy Immunol 2002;13(1):64-7. PubMed
    2. 26956. Giannattasio M, Serafini M, Guarrera P, et al. Contact urticaria from litchi fruit (Litchi chinensis Sonn.). Contact Dermatitis 1995;33(1):67.
    3. 26957. Raap U, Schaefer T, Kapp A, Wedi B. Exotic food allergy: anaphylactic reaction to lychee. J Investig Allergol Clin Immunol 2007;17(3):199-201.
    4. 96614. Valsecchi R, Leghissa P. Contact allergy due to lychee. Acta Derm Venereol. 2013;93(1):90-1. PubMed

    Promethazine

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

  • Swelling / A skin rash Additional detail

    Lychee

    Recorded for Lychee in the same Natural Medicines adverse-effect record shown under Hives above.

    Promethazine

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

Reported for Lychee but not commonly for Promethazine: shortness of breath, an allergic reaction and a severe allergic reaction.

Effects for Promethazine come from the ADVERSE REACTIONS section of its FDA label; effects for Lychee come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 22,361 voluntary FDA FAERS reports for Promethazine 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.

From our Q&A

Questions About Lychee or Promethazine

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

This page covers Lychee only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Promethazine page lists 83 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Alfalfa (moderate) and Angel's Trumpet (moderate).

By severity: 3 major · 57 moderate · 23 minor.

From our pharmacist’s overview on the Promethazine page

“Promethazine (Phenergan) is a phenothiazine antihistamine used for allergies, nausea, and motion sickness, and it is strongly anticholinergic on its own, causing dry mouth, blurred vision, drowsiness, and constipation. That is why the 83 supplements and herbs on this list deserve real attention, starting with the three rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Promethazine interaction page

One more smart check

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

We hold 98 real supplement products containing Lychee, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lychee. Even though Lychee itself has no known interaction with Promethazine, 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 Lychee and Promethazine 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 Lychee
Top half

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

29 days ago today
Medication Promethazine
Steady interest

#2,209 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 Lychee reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Lychee and Promethazine 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 .
Supplement

About Lychee

What is Lychee?

  • General nutrition and antioxidant support
  • Digestive complaints (traditional use)
  • Cough and sore throat (traditional use)
  • Blood sugar support (preliminary)
  • Weight and metabolic support (preliminary)

Lychee is a sweet tropical fruit that is nutritious and a source of vitamin C and antioxidant plant compounds. While the fruit is a healthy food for most people, supplement-strength extracts have only limited research behind specific health claims, and eating large amounts of unripe lychee on an empty stomach has been linked to dangerous low blood sugar in undernourished children. Talk to your pharmacist or doctor before using lychee extracts for any health condition.

Litchi chinensis · Sapindaceae · Fruit (pulp), seed, and peel; sometimes flowers and leaves · Fresh or dried fruit, juice, extract capsules, seed powder, teas

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

Lychee: dosing

There is no established standard dose for lychee supplements or extracts. The fruit itself can be eaten as a normal part of the diet in moderation.If you use a lychee extract or capsule product, follow the directions on the product label, and do not exceed the recommended amount.

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

Read the full Lychee monograph & all interactions
Medication

About Promethazine

What Is Promethazine Used For?

Brand name: Phenergan

Promethazine is used for a wide range of conditions. Tablets, oral solution, and rectal suppositories (brands including Phenergan, Promethegan, and Phenadoz) are approved for seasonal and perennial allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, hives (urticaria), angioedema, dermographism, and allergic reactions to blood or plasma. They are also used for motion sickness (both prevention and active treatment), nausea and vomiting related to anesthesia and surgery, sedation, and as a helper medication alongside pain relievers after surgery.

Promethazine hydrochloride injection (brands including Phenergan and Promethazine HCl injection) is used for many of the same purposes but is reserved for situations where oral treatment is not possible — including allergic emergencies as an adjunct to epinephrine, sedation during labor, and as an aid during certain surgical procedures such as bronchoscopy and eye surgery.

Most-Reported Side Effects for Promethazine

From FAERS, the FDA’s public side-effect reporting system (22,614 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dependence 3,586 reports
Nausea 2,646 reports
Vomiting 1,802 reports
Fatigue 1,496 reports
Diarrhea 1,341 reports
See full Promethazine drug information
Keep checking

Other Drugs & Lychee

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

0Major
86Moderate
121Minor
2,622No known interaction
86 Moderate 121 Minor 2,622 No interaction
Moderate

86 interactions

Showing 60 of 86 moderate interactions — see all 86 on the Lychee page.

Minor

121 interactions

Showing 60 of 121 minor interactions — see all 121 on the Lychee page.

No interaction 2,622 drugs checked — show the list

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

Showing the 60 most looked-up of 2,622 medications checked with no known interaction — see the full Lychee list.

See the full Lychee interactions page
See every supplement checked against Promethazine, ranked by severity
Evidence & sources

Lychee References

The 12 references that drive our Lychee 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.

  1. Niggemann B, Reibel S, Hipler C, Wahn U. Anaphylactic reaction to lychee in a 12-year-old girl: cross-reactivity to latex? Pediatr Allergy Immunol 2002;13(1):64-7. PubMed
  2. Giannattasio M, Serafini M, Guarrera P, et al. Contact urticaria from litchi fruit (Litchi chinensis Sonn.). Contact Dermatitis 1995;33(1):67.
  3. Raap U, Schaefer T, Kapp A, Wedi B. Exotic food allergy: anaphylactic reaction to lychee. J Investig Allergol Clin Immunol 2007;17(3):199-201.
  4. Guo JW. Effects of Litchi seed on enhancing insulin sensitivity in type 2 diabetic-insulin resistant rats. Chinese J New Drugs 2003;12:526-9.
  5. Zhao M, Yang B, Wang J, et al. Immunomodulatory and anticancer activities of flavonoids extracted from litchi (Litchi chinensis Sonn) pericarp. Int Immunopharmacol 2007;7(2):162-6. PubMed
  6. John TJ, Das M. Outbreaks of Hypoglycemic Encephalopathy in Muzaffarpur, India: Are These Caused by Toxins in Litchi Fruit?: The Point. Indian Pediatr. 2016;53(5):399.
  7. John TJ. Exploration of Association between Litchi Consumption and Seasonal Acute Encephalopathy Syndrome: Pediatric Infectious Disease Specialist's Viewpoint. Indian Pediatr. 2017;54(4):323-325. DOI
  8. Mathew JL. Exploration of Association between Litchi Consumption and Seasonal Acute Encephalopathy Syndrome: Evidence-based Medicine Viewpoint. Indian Pediatr. 2017;54(4):319-323. PubMed
  9. Shrivastava A, Kumar A, Thomas JD, et al. Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study. Lancet Glob Health. 2017;5(4):e458-e466.
  10. Spencer PS, Palmer VS, Mazumder R. Probable toxic cause for suspected lychee-linked viral encephalitis. Emerg Infect Dis. 2015;21(5):904-5. DOI
  11. Valsecchi R, Leghissa P. Contact allergy due to lychee. Acta Derm Venereol. 2013;93(1):90-1. PubMed
  12. Vashishtha VM. Outbreaks of Hypoglycemic Encephalopathy in Muzaffarpur, India: Are These Caused by Toxins in Litchi Fruit?: The Counterpoint. Indian Pediatr. 2016 May 8;53(5):399-402.

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 Lychee and Promethazine Together: Common Questions

Is it safe to take Lychee with Promethazine?
We do not list a known interaction between Lychee and Promethazine. 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 Lychee and Promethazine have any of the same side effects?
Yes — our sources link each of them separately to 4 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.
How was the Lychee and Promethazine combination checked?
Interactions in our licensed database are recorded against drug classes. Promethazine is filed under 4 classifications, and Lychee has documented interactions with 2 drug classes — none of Promethazine'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 Lychee interact with any other medications?
Yes. Lychee has 207 documented drug interactions in our database — Promethazine 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 Promethazine interact with any supplements?
Yes. Promethazine has documented interactions with 83 supplements in our database — Lychee is not one of them. The Promethazine 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

Lychee monograph Uses, safety profile, and every drug interaction in one place Promethazine drug information The full plain-English guide to this medication Promethazine supplement interactions Every supplement checked against Promethazine, 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 12 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Promethazine and Lychee?

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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.