A Brief Overview Thimerosal is a mercury-containing preservative that has been used since the 1930s. It is used to ensure that medical products stay potent and sterile. It has been used in medicines as well as medical products such as throat sprays and contact lens solutions.
Thimerosal contains a mercury compound called ethyl mercury.
In recent years, Federal agencies have developed specific guidelines to help prevent anyone from taking in too much mercury. Everyone is exposed to mercury during their lifetime. Thimerosal and Vaccines Thimerosal is added in tiny amounts to some vaccines to prevent them from spoiling and to keep germs from growing in the vaccine. There is no evidence that children have been harmed by the amount of mercury found in vaccines that contain thimerosal. Mercury exposure from vaccines containing thimerosal is within the safety margins included in exposure guidelines established by Federal agencies.