By applying direct Coombs' tests on 288 cases of various diseases mainly of liver disease the author obtained the following results. 1. Incomplete antibodies have been detected in 11 cases out of 33 acute hepatitis; in 6 out of 11 serum hepatitis; in 12 of 40 chronic hepatitis; in 10 of 29 liver cirrhosis; in 2 of 9 hepatoma; in 3 cases of acquired hemolytic anemia; in 2 cases of hypoplastic anemia; in one out of 4 essential thrombocytopenic purpura; in one of 6 Schönlein-Henoch's purpura; 2 of 4 Banti's syndrome; one Hodgkin's disease; in 2 lupus erythematodes; in one cancer of pancreas; in 2 ulcerous colitis; and in one of 21 acute and chronic hephritis, to the total of 57 cases. 2. Four cases of posthepatitic syndrome; 2 subacute yellow liver atrophy; one each of amyloid liver, liver-brain syndrome, and liver distomiasis, one each of congenital hemolytic anemia, familial non-hemolytic jaundice, and hemophilia, and one each of chronic lymphocytic leukemia and chronic myelogenous leukemia, 2 rheumatic arthritis, one periarteritisnodosa, 20 cholecystitis, 2 splenic venous thrombosis, 23 cases of gastric and duodenal ulcers, 16 hypertension, 9 diabetes, 4 Basedow's disease, 6 pericarditis lenta, and other 17 cases proved to be negative to direct Coombs' tests. 3. It has been clarified that incomplete antibodies can be detected in various diseases, but the incomplete antibody appears in a relatively high percentage especially in hepatitis and liver cirrhosis. However, even in the cases proved to be positive to Coombs' test the symptoms signifying an increase in hemolysis are often not necessarily distinct. Namely, of 57 cases responding pnsitive to Coombs' tests besides 3 cases of acquired hemolytic anemia, one acute hepatitis, one serum hepatitis, one chronic hepatitis, one liver cirrhosis, 2 hypoplastic anemia, one Banti's syndrome and one Hodkin's disease to the total of 11 cases demonstrated clearly the mechanism of hemolysis. Moreover, those who were suspected of hemolytic anemia amounted to the total of 8 cases; 2 acute hepatitis, 2 chronic hepatitis, one liver cirrhosis, one lupus erythematodes and one cancer of pancreas. 4. It has been clarified that there exists an immuno-hemolytic factor, derived from the so-called auto-immunization, plays an important role in a fair number of cases with the anemia, usually seen in the diseases such as liver, blood, collagen or malignant neoplastic diseases.