The anemia in experimental cholestatic jaundice has been studies in rabbits. A decreased erythrocyte deformability has been found in bile duct ligated animals and failed to be traceable in sham-operated ones. The deteriorated deformability of the red cells in a first step is caused by the action of surface active substances and secondly by other factors as a possibly deranged cell metabolism. Both factors will deteriorate the flexibility and thus the erythrocyte life-span.