The feeding of ethanol to experimental animals results in fatty infiltration of the liver. Recent findings have shown that ethanol-induced steatosis is accompanied by a lowering in hepatic S-adenosylmethionine (SAM) levels. It is known that SAM provides substrates for reduced glutathione formation and offers the cell protection from toxic metabolic oxidants. A recent study in this laboratory demonstrated that dietary supplementation with betaine generated increased SAM in the liver and protected against ethanol-induced steatosis. The present study not only showed that betaine supplementation to rats protects the liver from alcoholic steatosis, but also demonstrated that once steatosis is established, treatment with betaine partially reversed the steatosis after cessation of ethanol feeding. Furthermore, this study indicated that betaine supplementation to the diet had the capacity to attenuate steatosis despite the continued feeding of ethanol.