The invention discloses western medicine composition for obesity. The western medicine composition is prepared from raw materials in parts by weight as follows: 10-15 parts of soybean protein powder, 5-15 parts of olive oil, 1-5 parts of acetylsalicylic acid, 5-10 parts of linoleic acid, 3-5 parts of citric acid, 0.01-0.1 parts of vitamin A, 0.01-0.1 parts of beta-carotene, 0.01-0.1 parts of vitamin D, 0.01-0.1 parts of vitamin B1, 0.01-0.1 parts of vitamin B2, 0.01-0.1 parts of vitamin PP, 0.01-0.1 parts of vitamin C, 2-5 parts of xylitol, 5-8 parts of tartaric acid and 2-5 parts of promethazine hydrochloride tablets. The western medicine composition can remarkably reduce the weight and the food intake, reduce the level of HbA1c, LDL and TG in plasma, inhibit rising of blood glucose as well as reduction of expression of adipose tissue HMGB1 and raise the level of HDL and also has the advantages of simple preparation method, short treatment course, fast effect and little toxic and side effect.