The binding of 14C-taurine by subcellular fractions of rat brain cortex was studied in vitro. The binding was discovered to be more marked in the presence of phenytoin. The stimulant effect of phenytoin was found to be dose-dependent. The other anticonvulsant drug phenobarbital was not shown to have any noticeable effect on 14C-taurine binding. Analogous results were obtained during investigation of 14C-taurine incorporation into cell cultures of neuroblastoma C1300.