The purpose of this study was to evaluate the effect of taurine supplementation on plasma homocysteine (Hcy) levels, an independent risk factor of cardiovascular disease. The subjects consisted of 22 healthy middle-aged women (33 to 54 years). Serum lipids, plasma taurine and plasma Hcy levels were measured before and after supplying 3 g taurine per day for 4 weeks. The concentration of plasma taurine was significantly increased from 63.7 +/- 14.2 micromol/L to 73.8 +/- 16.6 micromol/L after taurine supplementation (p < 0.001). On the other hand, the concentration of plasma Hcy was significantly decreased from 8.5 +/- 1.2 micromol/L to 7.6 +/- 1.1 micromol/L after taurine supplementation (p < 0.05). The effect of taurine on the levels of plasma Hcy was assessed by regression analysis (R2 = 0.304). After taurine supplementation, plasma taurine and Hcy concentration exhibited a significant negative correlation (p < 0.05). In conclusion, taurine is an effective nutrient that antagonizes Hcy levels. Therefore, this study suggests that sufficient taurine intake might be an effective way of preventing cardiovascular diseases, such as atherosclerosis.