The property of pluronic F127 (PLF) as a base for an anticancer agent, mitomycin C (MMC) was evaluated. A weighed amount of PLF and MMC were slowly added to cold water and mixed completely. The solution was warmed to 37 degrees C and MMC containing PLF gel was formed. The cumulative amount of MMC which was released from the gel during a 3-hour period was calculated. 5.5 percent of MMC was released from PLF-MMC gel which contained 20 or 25% PLF and 3.8% MMC from PLF-MMC gel containing 30% PLF. Intraperitoneal (i.p.) administration of large amount of PLF gel alone in rabbits or mouse revealed severe hepatorenal toxicity, and acute i.p. administered LD50 of PLF was supposed to be between 1.7 g and 5.0 g/kg body weight in mouse. Further evaluation of gradual releasing property of PLF is needed.