Most US homes have at least one herbal product, vitamin supplement, and/or homeopathic medicine in the medicine cabinet. These products are often lumped together into the same category of dietary supplements, meaning they are exempt from the safety and efficacy regulations that the US Food and Drug Administration (FDA) requires for prescription and over-the-counter medications. Herbs are bioactive plant materials that are known or thought to affect the structure or function of the body. Vitamins are nutrients that mostly need to be obtained from the diet to support the body’s function and structure. Homeopathic products attempt to treat an individual with highly diluted substances intended to trigger the body’s natural healing system. Visit this section to learn more about commonly used herbal medicines and their side effects, warnings, and interactions. A list is also provided of herbal medicines that must be stopped 1 to 2 weeks before surgery, and those that cause sensitivity to the sun.