ANTITUMOR AGENT

PURPOSE:A safe antitumor agent containing a lactose ester of a fatty acid obtained by condensing lactose with a specific fatty acid as an active constituent with side effects. CONSTITUTION:An antitumor agent containing a lactose ester of a fatty acid obtained by condensing lactose with an 8-22C saturated or unsaturated fatty acid, e.g. stearic, caprylic, palmitoleic or oleic acid, as an active constituent. The active constituent is dissolved or suspended in physilological saline solution and administered orally or intravenously. The dose thereof is 10-5mg/kg/day for the oral administration, and 1-5mg/kg/day for the intravenous administration. The lactose ester of the fatty acid may be an emulsifiable substance, having the number of introduced fatty acid of about 1-3 (molar ratio) into the lactose, soluble in cold-warm water, and capable of giving an aqueous solution having a very high ability to reduce the surface tension thereof.