To obtain a cosmetic or composition for a dermal medicine capable of obtaining effects on a weight reduction counter measure for excessive flesh on thigh and waist parts, tightening skin, especially the prevention and treatment of cellulite or orange skin and/or tightening of the outline of a face.

This cosmetic or composition for dermal medicine having the weight reduction effect contains at least 1 kind of a diterpene selected from cafestol, carveol and their chemical derivatives in a medium safe for human body. Also, the cosmetic or composition for dermal medicine having the weight reduction effect contains at least 1 kind of the diterpene in the medium safe to the human body and also contains at least 1 kind of fat-decomposing component selected from methylxanthines to begin with caffein, theobromine, aminophylline and theophylline different from the above diterpenes.