Non-alcoholic steatosis of the liver is a common condition. It usually consists of triglyceride drop deposits in macro- or microvacuoles of the hepatocytes and may result from various disturbances of lipid metabolism, notably accumulation of fatty acids in the liver and decrease in the secretion or synthesis of lipoproteins. The causes of steatosis are numerous. It is important to distinguish between severe steatosis (acute steatosis of pregnancy, toxic steatosis, Reye's syndrome), where most of the deposits are in microvacuoles, and incidental or moderate steatosis of nutritional or hormonal origin, or developed during idiopathic enterocolitis or various liver diseases. Treatment, sometimes intensive, essentially depends upon the cause of steatosis.