FIELD: medicine, pharmacy. SUBSTANCE: invention relates to methods of preparing fluorouracil-base antitumor composition designated for injections. Method of preparing involves preparing fluorouracil solution by dissolving sodium hydroxide taken in the amount 13-17 g/l in water for injection followed by addition of fluorouracil taken in the amount 45-55 g/l. Before addition of sodium hydroxide water is subjected for treatment by ultrasonic oscillation in frequency 1.0-1.5 MHz for 10-15 min. Invention provides development of simple and available form of medicinal agent as injections. EFFECT: improved method of preparing, enhanced solubility of fluorouracil in water. 1 tbl
