Taurine (2-aminoethanesulfonic acid) is known to have a cardiotonic action. The present study was designed to see whether oral treatment with taurine could improve the status of congestive heart failure induced by aortic regurgitation. Nine rabbits were treated daily with taurine (100 mg/kg) after producing aortic regurgitation. Cumulative mortality at 8 weeks in the non-treated group was 52% compared with 11% in the taurine-treated group (p less than 0.05). Cardiac function (max dP/dt) was significantly decreased in rabbits with aortic regurgitation, whereas in taurine-treated rabbits, cardiac function was maintained the same as control. The present data suggest that taurine prevented the rapid progress of heart failure, and consequently prolonged the life expectancy.