Nonalcoholic fatty liver disease (NAFLD) is now the most frequent chronic liver disease and the most frequent cause of the abnormal activity of aminotransferases. It affects about 25% of the global adult population. In the article the current principles of diagnosis and treatment of NAFLD are presented. The questions frequently asked by family doctors are answered, and the responses are thoroughly discussed. The role of ursodeoxycholic acid (UDCA) in the therapy of nonalcoholic steatohepatitis (NASH) is emphasised.