Caffeine is so widely consumed around the world in coffee, tea, soft drinks, and other beverages and foods that you may not think of it as a medicine. But it does act as a stimulant and a few people report having seizures after they consume it. It has even been used to prolong purposely induced seizures in psychiatric patients being treated for depression with electroconvulsive therapy ("shock treatments").

Besides coffee, tea, cocoa, and cola, you can also find caffeine in less well-known substances like guarana (Paullinia cupana) and maté (Ilex paraguariensis). It also appears in combinations of medications and supplements, so if you don't read the label carefully you may take it unintentionally. The risks may be greater if it's combined with other stimulants like ephedra.

Read more about maté in the "About Herbs" section of the Memorial Sloan-Kettering Cancer Center website. (If you have not visited the site before, the information on maté will be preceded by a Disclaimer.)

Much of the information in this article is based on Spinella M: Herbal medicines and epilepsy: The potential for benefit and adverse effects. Epilepsy Behav 2001; 2(6):524-532. (PMID 12609386)

Topic Editor: Steven C. Schachter, M.D.
Last Reviewed:12/15/06