Steatosis is defined by hepatocyte accumulation of lipids. Different types of steatosis are described (macro-, medio- and microvacuolar). Macrovacuolar steatosis is a common lesion, mainly observed during metabolic syndrome and excessive alcohol consumption. Steatohepatitis combines steatosis, the presence of ballooned hepatocytes and lobular inflammatory foci. Liver fibrosis is the main consequence of steatohepatitis. Liver biopsy is the gold standard diagnostic test.