Weanling mice of the DBA/2J strain are spontaneously audiogenically seizure prone between 19 and 24 days. Thereafter, susceptibility declines rapidly within the next 7-10 days. It was found that thiamine tetrahydrofurfuryl disulfide (TTFD) significantly delayed the natural disappearance of seizure proneness in male animals compared with controls treated with identical doses of saline. There was no significant difference between treated females and controls. Evidence is presented that suggests that TTFD is cholinergic in its action and has pharmacologic effects other than a simple vitamin replacement. The difference between males and females found in this strain of mouse in this experiment is consistent with previous information which indicates that sex-related differences exist in their response to stress.