Throughout the world people who have epilepsy and seizures are prohibited from donating blood. These restrictions are based on the assumption that they are prone to adverse donor reactions, specifically, syncope and convulsions. We describe a study evaluating whether that concern is warranted. During a two year period beginning in 1987, blood donors with a history of seizures were actively recruited by the American Red Cross in the state of Maryland, USA. According to accepted standards, adverse reactions were classified as "slight", for dizziness and nausea without loss of consciousness; "moderate", denoting syncope; and "severe", indicating convulsive syncope. We reviewed a total of 329,143 satisfactory blood donations, and 613 individuals reporting a history of seizures donated blood 723 times. Among donors with seizures, 186 (25.7%) were taking antiepileptic medication, and 61 (8.4%) had one or more seizures in the preceding year. Individuals with seizures had a low incidence of adverse reactions (3.34%). Although slightly higher than the entire population (2.24%), this difference was not statistically significant. In particular, the risk of syncope with or without convulsive activity was low for people with seizures (.21%) and not significantly increased as compared to other donors (.28%). Our study supports the view that individuals with seizures or epilepsy are not at greater risk for adverse reactions after blood donation. Major restrictions on individuals with epilepsy and seizures as blood donors are not warranted.