Teratogenic agents are defined as physical, chemical, or biological agents or nutrient deficiencies that lead to fetal structural or functional alterations. Information on the effects of exposure to teratogens during pregnancy is of the utmost importance. In order to achieve this goal, in 2001, the Bahia State Teratogen Information Service was created in the Medical Genetics Department at the University Hospital of the Federal University in Bahia. The current paper aimed to describe the first four years of operation in the service. From March 2001 to May 2005, the service was consulted by telephone, fax, and e-mail. During this period, 408 queries were made, for a total of 1,091 different reasons. Most queries were made by pregnant women and health care professionals. Hair products, herbal teas, and misoprostol were the most widely investigated agents. The low number of queries (average 1/day) shows the need for more awareness-raising on the risks posed by the various agents.