NEW MATERIAL:A purified extract of bark of Melia azadirachta (color and shape: lyophilized extract is white powder; soluble in water, insoluble in organic solvents such as methanol, etc.; color reaction: positive in phenol sulfuric acid reaction and anthrone sulfuric acid reaction, colored in bluish green by the addition of iodine).

USE: A remedy for cancers.

PROCESS: Bark of Melia azadirachta is extracted with hot water, and the extract is purified by alcohol precipitation method (e.g., an alcohol such as methanol, etc. is added to it, and the formed precipitate is collected by a method such as centrifugation, etc.) or dialyzing film method (e.g., it is put in a dialyzing film, immersed in water, dialyzed, and the inner solution of the dialysis is concentrated to dryness to give an extract). The prepared purified extract is dissolved in water, the aqueous solution is subjected to molecular sieve treatment using a molecular sieve agent capable of fractionating 1×103W1×105 or 1×103W2×105 molecular weight, the first fraction is collected from the three separated polysaccharide fractions, to give a purified antitumor extract of bark of Melia azadirachta.