Why does acid cause hemolysis?

Can be avoided: Acetylsalicylic acid (aspirin) can cause severe hemolytic (i.e., breakdown of red blood cells with release of hemoglobin) anemia in certain individuals who are born with a deficiency in a particular enzyme (glucose-6-phosphate-dehydrogenase -- g6pd), an enzyme needed for rbcs to function properly. Once the triggers are identified (and avoided), you can lead a healthy and active life.

Denatures hemoglobin: In the lab, acidic solutions will denature hemoglobin, causing the red cell to hemolyze. Fetal hemoglobin is more resistant to this. This difference is the basis of a test to determine how much fetal blood is mixed in the maternal blood system of mom's who are rh negative, and thus need rhogam.