Serum consistuents were determined for 14 healthy pigs after the addition of hemolysates containing 54, 133, 215 and 400 mg/dl of hemoglobin to serum. Of sixteen chemical procedures considered, changes (P<0.0005) in creatinine, total protein, Pi, alanine aminotransferase (ALT), lactate dehydrogenase (LDH), Ca, K, aspartate aminotransferase (AST), total bilirubin and albumin values occurred following the addition of a hemolysate containing 400 mg/dl of hemoglobin. Changes (P<0.0005) were also observed in certain serum constituents when hemolysates containing 54, 133 and 215 mg/dl of hemoglobin were added.