Herbs for People Taking Many Medicines: A Pharmacist-Centered Approach

Check with a pharmacist before adding any herb to a list of medicines. The NHS says to check first with a pharmacist before taking a herbal medicine if you already take other medicine, including medicine bought without a prescription. [1] Do not stop or change a prescribed medicine on your own; ask the prescriber or pharmacist.

Why a long medicine list changes the question

Taking many medicines at once is called polypharmacy. A UK survey of 155 adults aged 65 or older who took prescription medicine found that 33.6% also used herbal products or dietary supplements, and about a third of those users (32.6%) were at risk of a potential harmful interaction. [2] A smaller US-Mexico border survey of 130 older adults found that 72.3% took multiple medicines and 31.5% were at risk of at least one possible interaction involving a herb or supplement. [3] Both are small surveys and show risk of an interaction, not harm that happened. A 2025 review of 16 studies found supplement use alongside medicines in 23% to 82.5% of older adults, with the highest concern for blood thinners, for example warfarin with ginkgo. [4]

What is documented and what is only possible

NCCIH says most herb-drug interactions in current sources are hypothetical, inferred from animal or cell studies, and that attention is needed for medicines with a narrow margin of safety such as cancer chemotherapy, warfarin and digoxin. [5] That means three levels, which the safety library explains in How Interactions Work: documented in people, reported in single cases, and theoretical.

The NHS lists statins, antidepressants, diabetes medicines such as metformin, blood pressure medicines such as ramipril, blood thinners such as warfarin and hormonal contraception as medicines that do not mix well with herbal medicines. [1] It also says herbal medicines should not be taken in pregnancy, breastfeeding, or with kidney or liver problems. [1]

The pharmacist-centered approach

This is a way of organizing the conversation, not dosing advice.

1. Make one complete list. Include prescriptions, over-the-counter medicines, vitamins, herbs, teas and extracts. Use the Medicine and Supplement List Worksheet or the Printable Medicine and Supplement List. Why: a study of 78 patients found that the most common theme promoting disclosure was the provider asking, and that non-disclosure related to patients believing supplements are safe or not important. [8]
2. Bring the products or photos of the labels, as described in Medication and Supplement Review. Labels can differ from contents; NCCIH notes the FDA has found prescription drugs, including warfarin and phenytoin, in products sold as supplements. [9]
3. Ask one pharmacist who sees your whole list to check each herb against each medicine. FDA advises talking to a doctor, pharmacist or other health professional before deciding to use a supplement. [10] See Questions to Ask Your Pharmacist About Herbs and Supplements and How to Check an Interaction Safely.
4. Ask about stopping, not only starting. A clinical review for physicians caring for older people says supplements contribute to polypharmacy and may be targeted for "deprescribing" if risk outweighs benefit, as part of a patient-centered approach. [11] Deprescribing is a decision made with the prescriber, not alone.
5. Watch for duplicates across products. See Amounts and Duplicate Ingredients.

Extra care points

• Older adults: see Herbs for Older Adults and Older Adults: More Medicines, More Interactions.
• Blood thinners: Herbs and Blood Thinners.
• Before surgery: NCCIH says certain supplements may increase bleeding risk or affect the response to anesthesia, so tell providers well ahead. [9] See Herbs Before and After Surgery.
• Checking tools: How to Check a Herb for Interactions.