Jaundice, a common condition with many different causes, is marked by yellow discoloration of the sclerae, mucous membranes and skin. Apart from a careful history and clinical examination, the determination of the liver enzymes is the most important step to unravel the underlying etiology. The most common etiology for an isolated hyperbilirubinemia with normal liver values is Gilbert's disease. If the liver enzymes are abnormal, the relationship between transaminases and cholestatic enzymes allows to distinguish between a hepatocellular and cholestatic dysfunction and to guide the further diagnostic and therapeutic modalities accordingly.