Spearmint - Research:
Most of the studies done on spearmint are laboratory or animal trials. One recent human study showed that chewing spearmint gum while studying has positive effects upon memory.6 There are currently no studies on the external use of spearmint
Spearmint is most commonly utilized for its scent or flavor in various internal and external products. The oil is used to flavor jellies, sauces, chewing gum, candy, iced tea, mouthwashes, toothpastes and breath mints.3 It is also used as a scent in perfumes.1 Though not quite as potent (and therefore less commonly used) as peppermint, M. spicata has been used to soothe indigestion, and other GI discomfort.1,2,3 The main constituent of the spearmint oil, called carvone, is reputed to have antiseptic properties.5
1 Grieve M. A Modern Herbal. Vol. 2. New York: Dover Books; 1971.
2 Bown D. The Herb Society of America New Encyclopedia of Herbs and Their Uses. London: Dorling Kindersley Ltd.; 2001.
3 Onstad D. Whole Foods Companion: A Guide for Adventurous Cooks, Curious Shoppers & Lovers of Natural Foods. White River Junction, VT: Chelsea Green Publishing Company; 1996.
4 Spearmint. Wikipedia Encyclopedia web site. Available at: http://en.wikipedia.org/wiki/Spearmint. Accessed on December 14, 2005.
5 Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine. Rochester, VT: Healing Arts Press; 2003.
6 Baker J, Bezance J, Zellaby E, et al. Chewing gum can produce context-dependent effects upon memory. Appetite. October 2004;43(2):207-10.