Propylene glycohethanohwater (5:1:4) given intravenously for 2 weeks to rats and dogs resulted in hematuria and hematologic changes consistent with intravascular hemolysis. Several combinations of propylene glycol, polyethylene glycol 400, ethanol, saline and/or water were then studied for hemolytic activity both in vivo in rats after intravenous administration and in vitro. Solutions containing propylene glycol:ethanol:saline (1:3:6), ethano:lsaline (3:7), and polyethylene glycol 400:ethanol:water (3:2:5) were found to cause less hemolysis in vivo than the other solutions tested. Polyethylene glycol 400:ethanol:water (3:2:5) was chosen for further evaluation and when given intravenously to dogs for 1 week or rats for 2 weeks, this solution caused no adverse hematologic effects.