Our previously published study presented a prospective association of vitamin D levels with occurrence of hepatic decompensation. Furthermore vitamin D deficiency was associated with high mortality in cirrhotic patients dependent on liver dysfunction. Concerning this aspect the main point is to investigate in this study whether low vitamin D status is the consequence of increasing deterioration of the liver synthesis or may even contribute to liver dysfunction. Low synthesis of vitamin D in the skin can be the result of reduced sunlight exposure and malnutrition and/or malabsorption in cirrhotic patients. On the other hand, organ dysfunction may impair the activity of 25-hydroxylase in the liver. Despite the above mentioned correlation between vitamin D deficiency and liver dysfunction there is still insufficient evidence to recommend oral vitamin D supplementation as a concomitant therapy in clinical practice because there exists no adequately designed randomized controlled trial that evaluates the necessary daily oral dose on vitamin D.