Five percent dextrose in water (D5W) and lactated Ringer's (RL) are two intravenous solutions that are incompatible with citrate phosphate dextrose (CPD) anticoagulated RBCs. Hemolysis, agglutination, and clotting can occur when RBCs are mixed with, infused together with, or transfused in the same line following administration of these fluids. Although minimal plasma remains in units of RBCs containing adenine-saline-dextrose solution (ADSOL; Fenwal Laboratories, Deerfield, IL), clots are seen immediately after contact is made with RL. Clumping and hemolysis are seen when ADSOL-stored RBCs or saline-washed RBCs are mixed with D5W. This study reinforces the unsafe practice of mixing RBCs with certain intravenous solutions.