For thousands of years, herbs have been used as medicines. In fact, many present-day pharmaceutical drugs were developed based on the active compounds found in plants. Today, the National Institutes of Health’s Office of Dietary Supplements indicates that about 20% of the adult population takes an herbal supplement. The 1994 Dietary Supplement Health and Education Act defines an herbal supplement as a plant (other than tobacco), algae or fungi consumed by mouth as a pill, capsule, tablet or liquid.

Finding accurate clinical information for any health condition can be challenging, especially with regard to herbal products. Herbal benefits often are based on folklore claims, and there can be confusion over benefits and risks for many plants because they are specific to the plant variety. For example, reliable scientific information exists for American and Siberian ginseng, but not Asian ginseng. For those seeking information, the Office of Dietary Supplements Fact Sheets are a good place to start evaluating supplements for efficacy and safety. Go to 808ne.ws/botanicalfacts.

Many herbal supplements do not list the plant variety, or the supplement contains a combination of one or more botanical compounds, making it nearly impossible to determine if any negative interactions or potential health risks are likely. The 1994 dietary supplement act does not require herbal product manufacturers to prove their products are safe or effective before selling them.

Question: Are organic herbal supplements safer than other supplements?

Answer: Plants take up the nutrients and other compounds found in the soil where they are grown. Plants labeled organic are not required to be grown in soil free of toxic heavy metals such as lead, arsenic or cadmium, so it could be beneficial before purchasing an herbal supplement to contact the supplement companies and inquire if they test for heavy metals. Be aware that herbal ingredients from Asia are often found to have heavy metals.

Q: What other precautions should a person take before purchasing an herbal supplement?

A: Herbal supplements are natural sources of medicinal compounds. And like drugs, precautions related to mixing medications also apply to herbs taken with medications. The Medscape drug-interaction checker includes reliable information on general herb compounds, indicating the type of interactions. The site can also be used to check how alcohol (use the search term “ethanol”) interacts with medications and supplements. Go to 808ne.ws/druginteraction.

A good rule of thumb is to be cautious when considering products containing herbs, especially those with multiple components or if you are taking medications. Your pharmacist can be another good source of information, especially if you are taking any medications. Stay safe — get informed.

Joannie Dobbs, Ph.D., C.N.S. and Alan Titchenal, Ph.D., C.N.S. are retired nutrition faculty from the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa.