Herbal Supplement and Drug Interaction Cheat Sheet
Many herbal supplements can affect the way various drugs interact with the body. Use this table
to help identify potential drug interactions of herbal supplements your patients or clients may be
taking.
Herbal Supplement
Drug
Interaction
Aloe vera
May cause hypoglycemia; may cause cardiac
Hypoglycemics, digoxin, and toxicity due to electrolyte imbalance; laxative
thiazide
effect can cause diarrhea that may decrease
drug absorption
Bitter orange
MAO inhibitors
May increase heart rate and blood pressure
Borage
Anticonvulsants
May lower seizure threshold
Chasteberry
Birth control pills
May affect hormone levels
Echinacea
Cyclosporine, corticosteroids
Possible immunostimulant may reduce drug
effectiveness of immunosuppressants
Elder, European
Drugs that increase urination
Diuretic effect can be additive
Ephedra (ma huang)
Anticonvulsants, heart and
blood pressure medications,
hypoglycemics
May lower seizure threshold; may increase
heart rate and blood pressure; may affect
blood sugar
Evening primrose
Anticoagulants;
anticonvulsants
May increase bleeding; may lower seizure
threshold
Feverfew
NSAIDs
May negate effect of herb in treating migraine
headaches
Garlic
Anticoagulants, saquinavir
(used to treat HIV infection)
Can thin blood; interaction may exist with
saquinavir
Ginkgo
Anticoagulant
May increase bleeding risk
Ginseng, American
Estrogen, corticosteroids
May enhance hormonal response
Ginseng, Asian
hypoglycemics; digoxin
May cause hypoglycemia; may interfere with
drug action and monitoring
Hawthorn
Heart medications
Not thoroughly studied, but interaction may
exist
Kava
Parkinson’s disease (PD)
medications, anesthetics
Interaction may exist with PD medications;
may enhance drug action of anesthetics
Kelp
Synthroid, other thyroid
hormone replacers
Iodine interferes with drug action
Lavender
Sedatives
May increase drowsiness
Licorice root
Diuretics, corticosteroids (or
other medications that lower
potassium levels), digoxin
May cause dangerously low potassium levels;
may interfere with drug action and monitoring
Milk thistle
Hypoglycemic
May cause hypoglycemia
Parsley
Antihypertensives, MAO
inhibitors
May increase risk of high blood pressure or
hypertensive crisis
Passionflower
Sedatives
May increase drowsiness
Peppermint oil
Antacids
Coating of peppermint oil capsules may break
down more quickly and increase risk of
heartburn
Pomegranate
Anticoagulants
Interaction may exist
Saw palmetto
Iron supplement
Tannins in herb inhibit iron absorption
St. John’s wort
Antidepressants, birth
control pills, cyclosporine
digoxin, indinavir,
irinotecan, phenytoin and
phenobarbital,
anticoagulants; iron
supplement
Interactions may exist with many drugs;
tannins in herb inhibit iron absorption
Tea, black
Iron supplement
Tannins in herb inhibit iron absorption
Tea, green
Anticoagulants
Small amounts of vitamin K may decrease
effectiveness of anticoagulants
Valerian
Anesthetics, barbiturates
May enhance drug action of anesthetics; may
cause excessive sedation
Yohimbe
MAO inhibitors
Effects may be additive
References and recommended readings
Herbs at a glance. National Center for Complementary and Integrative Health website.
https://nccih.nih.gov/health/herbsataglance.htm. Accessed May 15, 2015.
Jensen B. Herbal drug interaction chart. Kansas State University website.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&ved=0CEEQFjAI&url
=http%3A%2F%2Ffaculty.ksu.edu.sa%2Fhisham%2FDocuments%2FPharmacy_Docs%2Fherba
l_drug_interactions.pdf&ei=w5BDVYv8E4iegwSb1YGQCA&usg=AFQjCNF9sAS8PxVtUJwD
0nzXPYqCW2cLBw&sig2=WW0Rijd_5tH0BZDfLnUOTg&bvm=bv.92189499,d.eXY&cad=rj
a. Published July 2003. Accessed May 15, 2015.
Pronsky ZM, Dorwe JP. Food-Medication Interactions. 17th Ed. Food Medication Interactions;
2012.
Rolfes SR, Pinna K, Whitney E. Medications, herbal products, and diet-drug interactions. In:
Rolfes SR, Pinna K, Whitney E. Understanding Normal and Clinical Nutrition. 8th Ed. Pacific
Grove, CA: Brooks Cole; 2008: 647.
Contributed by Jamie Marchetti, MS, RDN
Review date: 4/23/15