A sweat gland disorder called hyperhidrosis causes excess perspiration. While the exact cause is unknown, the problem may have to do with abnormal reactivity of sweat glands to changes in temperature and to physical and emotional stress. Hyperhidrosis can affect the feet, palms, underarms, or the whole body. According to the National Institutes of Health, hyperhidrosis affects between two and three percent of the U.S. population but fewer than 40 percent of those affected seek medical help.
I discussed your question about sage with Tieraona Low Dog, M.D., director of the Fellowship at the Arizona Center for Integrative Medicine and an expert on botanical medicine. She tells me that sage has a very long history of use for combating excessive perspiration and that she has successfully used it for this purpose with several patients. Dr. Low Dog says that sage leaf is approved by German health authorities for the treatment of hyperhidrosis and that it is included in a number of formulations for relief of hot flashes and night sweats. To use sage, Dr. Low Dog recommends buying dried leaf in capsules and taking 1,000 mg twice a day. She notes that sage is quite safe in this form but should not be used by pregnant women because it can cause uterine contractions. She also warns against using essential oil of sage, which is high in thujone, a potentially toxic compound.
Andrew Weil, M.D.