• Previous studies have pointed to wake electroencephalographic changes associated with oral contraceptives. This investigation sought to determine if sleep EEG activation would show additional EEG-oral contraceptive relationships not previously suspected. With blind procedures, oral contraceptive and EEG data were collected on 110 adult women. Three age-equated comparison groups were formed: (1) never used pill (control); (2) previously used pill without side effects (asymptomatic); and (3) previously used pill with side effects (symptomatic). Analyses indicated a significant statistical relationship between paroxysmal EEGs and symptomatic pill use. No difference in paroxysmal EEG incidence existed between control and asymptomatic pill use groups. Among prior pill users, women with paroxysmal EEGs reported almost twice the side effect incidence (81.3%) as did women with normal EEGs (42.1%).