Book excerpt: Today, many manufacturers of plant-based "neuroceuticals" claim their products can offer powerful benefits in brain function. However, the US government does not require these manufacturers to demonstrate their products’ effectiveness, leaving it difficult for consumers and health professionals to make decisions about the benefits and risks. In Herbal Supplements and the Brain: Understanding their Health Benefits and Hazards, two leading researchers provide this crucial information in clear language any intelligent reader can understand and use. They begin by introducing the fundamental principles of pharmacology, explaining how drugs and natural products can affect the body’s organs and organ systems. Using examples, they show how to determine whether an ingested substance can enter the bloodstream and reach its target at a concentration sufficient to have an effect. They also explain how natural products may influence blood levels of other substances, and discuss whether such interactions may diminish the effectiveness of prescription medications or alter normal body chemistry. Throughout, the authors emphasize factors relating especially to neuroceuticals and the brain. Individual chapters are devoted to nutritional supplements which promise to enhance memory, relieve pain, safely promote sleep, and aid in the treatment of depression or anxiety. Specifically, readers will find research-based coverage of Ginkgo biloba; St. John’s Wort; Valerian; Lemon Balm; Kava; Lavender; Kudzu, Daffodil, Passion Flower, and Camellia Tea and other caffeinated beverages.