Cholestasis is associated with anemia, a disorder attributed to hemolysis, i.e. the necrotic death of erythrocytes. Alternatively, erythrocytes may undergo suicidal death or eryptosis, characterized by cell shrinkage and phosphatidylserine (PS) exposure at the erythrocyte surface. Eryptosis may be triggered by an increase in cytosolic Ca²⁺ ([Ca]_i) and by ceramide. The present study explored whether bile acids induce eryptosis. Annexin V-binding reflecting PS exposure, forward scatter reflecting cell volume and Fluo3 fluorescence reflecting [Ca]_i were determined in erythrocytes, ceramide by utilizing fluorescent antibodies. Lithocholic acid and taurolithocholic acid significantly enhanced the percentage of annexin V-binding erythrocytes, effects paralleled by cell shrinkage and by increase in [Ca]_i, but did not induce significant hemolysis and only slight ceramide formation. In freshly drawn blood the percentage of annexin V-binding cells was significantly higher in patients suffering from cholestasis and/or liver insufficiency (1.6 0.2%) than in patients without liver diseases (1.0 0.2%). In conclusion, bile acids may stimulate eryptosis both in vitro and in vivo, an effect possibly contributing to anemia in cholestasis and, as PS-exposing erythrocytes adhere to the vascular wall, to deranged microcirculation.