Hemolytic anemia is a well-recognized complication of sulfasalazine treatment. 
17 of 40 (43%) patients with inflammatory bowel disease receiving sulfasalazine 
had evidence of hemolysis as detected by starch gel electrophoresis. Only 47% 
(8) of patients with hemolysis had Heinz body formation. The hemoglobin was 
significantly reduced in patients with hemolysis and 53% had a reticulocyte 
count of greater than 5%. A significant correlation was noted between hemolysis 
and serum sulfapyridine level, but no correlation was seen with serum 
sulfasalazine level. There was no significant difference in disease extent or 
activity in patients with hemolysis compared to those without hemolysis. 
Hemolysis is not a rare side-effect of sulfasalazine therapy. Heinz body 
formation is not invariably found in sulfasalazine-induced hemolysis.