Recently findings indicate that taurine is involved in apoptosis regulation. We studied now the possible neuroprotective effect of taurine in ethanol-induced apoptosis of cerebellar granular neurons and Purkinje cells. The experiments were performed on male mice at the postnatal days P4 and P7, the ages of maximum sensitivity to ethanol of Purkinje cells and granular neurons, correspondingly. The animals were divided into 3 groups: ethanol-treated, ethanol + taurine-treated and controls. Ethanol (20% solution) was administered subcutaneously at a total dose of 5 g/kg (2.5 g/kg at time 1 h and 2.5 g/kg at 3 h) to the ethanol and ethanol + taurine groups. The ethanol + taurine group also received two injections of taurine (1 g/kg each, at time zero and at 4 h). Twelve (P4) and eight (P7) hours after the first ethanol injection the cerebella were fixed in 4% paraformaldehyde and embedded in paraffin. To estimate apoptosis, immunostaining for activated caspase-3 and TUNEL staining were made in the mid-sagittal sections containing lobules I-X of the cerebellum. The number of activated caspase-3-immunoreactive and TUNEL-positive Purkinje cells (P4) and granular neurons (P7) markedly increased after ethanol administration. Taurine treatment did not affect the number of activated caspase-3-immunoreactive or TUNEL-positive Purkinje cells at P4. Contrary to that, taurine significantly decreased the number of activated caspase-3 and TUNEL-positive granular neurons at P7 in all lobules. We thus conclude that taurine has different effects on ethanol-induced apoptosis in Purkinje cells and granular neurons. This study was supported by the competitive research funding of the Pirkanmaa Hospital District and the Finnish Cultural Foundation.