Oral taurine at doses of 375 to 8,000 mg/day (16 to 150 mg/kg/day) was administered to six patients with mixed seizure disorders refractory to standard anticonvulsant treatment. No improvement in seizure control was observed. During taurine tolerance testing, a substantial rise in plasma growth hormone concentration was noted in four of the six patients. Mean baseline concentrations of 3.0 +/- 2.3 and 1.3 +/- 0.9 ng/mL were increased to mean peak concentrations of 17.1 +/- 2.4 (P less than .005) and 20.4 +/- 5.1 ng/mL (P less than .025), respectively. Cerebrospinal fluid homovanillic acid (HVA) concentration was also noted to be higher in two of three patients two weeks after initiation of tauerine. Initial HVA concentrations of 20.3 and 28.2 ng/mL increased to 37.2 and 54.2 ng/mL, respectively. The possible effect of taurine on central dopaminergic mechanisms is discussed.