There are excellent resources available to assist them. The Natural Medicines Comprehensive Database is highly respected and updated daily, although there is an annual fee to access its information. If all else fails, ask for a referral to a practitioner who is familiar with herbs and supplements. You can find useful, free information about herb, supplement and drug interactions on The Natural Pharmacist Web site. There is a growing amount of information about drug interactions and side effects involving herbs and supplements.
Some information comes from voluntary reports by doctors, pharmacists or consumers.
Other information comes from human studies about the effectiveness of an herb or supplement for treating a specific health problem. However, unlike drug manufacturers, herb and supplement manufacturers are not required to gather or report interaction or side effect information about their products. Because of this, many interactions and side effects go unreported. A 1999 survey estimated that 12 percent of people who used herbs or supplements experienced an interaction or side effect. You can ask your pharmacist or prescriber for information and watch for health news reported in newspapers, magazines, on TV, radio, or via the Internet.