Previously, we demonstrated with 7-day-old mice that taurine (2 g/kg) saves about 50 % of dying cerebellar neurons from ethanol-induced apoptosis. However, a further increase in the taurine dose had a toxic effect and killed ethanol-treated mice. Taurine at the dose of 4 g/kg co-administered with ethanol (5 g/kg) killed 50 % and at the dose of 6 g/kg 100 % of 7- day-old mice. In the present study we repeated our experiments with adult (5–6 months) and old (12–13 months) mice. Taurine and ethanol were injected in two half-doses: taurine at 0 h and at 4 h and ethanol at 1 h and 3 h. During 14 days after treatment mice were monitored to obtain signs of toxicity or death of animals. Co- administration of taurine (10 g/kg) with ethanol (8 g/kg) killed 100 % of adult mice. In the old mice the lethal dose was 6 g/kg of taurine co- administered with 6 g/kg of ethanol. All mice treated with ethanol or taurine alone survived. The adult and old mice dying from combined ethanol and taurine toxicity showed a marked fall in the blood glucose level. We assume that the drop in blood glucose after the taurine and ethanol co-administration can be one reason of lethality. Comparison of the lethal doses of taurine and ethanol co-administration in 7-day- old, adult and old mice allows us to conclude that the adverse effects of taurine and ethanol combined toxicity is age-dependent. This research was supported by the competitive research funding of Pirkanmaa Hospital District and Finnish Foundation for Alcohol Studies.