The agent, 1,3-bis(3-chloroethyl)-1-nitrosourea (BCNU), when given by arterial infusion for brain tumor chemotherapy is usually dissolved in an alcohol/saline solution. The authors compared the osmolality of and drug recovery from solvent systems of alcohol/saline, dimethyl sulfoxide (DMSO)/water, and dextrose/water. Recovery of drug was adequate from all solvent systems, although variability of drug recovery from the alcohol/saline and DMSO/water systems was greater than from the dextrose/water system. The alcohol/saline system was significantly hyperosmolar. The alcohol/saline and DMSO/water solvent systems offer no advantage over the dextrose/water system and may be associated with significant disadvantages.