A composition comprising a therapeutically effective amount of Bidens pilosa extract, or an active compound isolated from the Bidens pilosa extract for use in treating obesity, reducing body weight or body weight gain, and/or gaining muscle mass or muscle content in a subject in need thereof is disclosed. The composition is useful for reducing fat cell size and/or fat accumulation in the fat cell in a subject in need thereof. The composition may further comprises an animal feed. A polyacetylenic compound for use in treating obesity, gaining muscle mass or muscle content, and/or increasing lean tissue protein content in a subject in need thereof is also disclosed. In one embodiment, the polyacetylenic compound is cytopiloyne.本發明提出一種組合物用於製備一目標動物所需之治療肥胖、降低體重或減少體重增加及/或增加肌肉組織或肌肉含量的醫藥組合物之用途，其中該組合物包含治療有效量之一咸豐草萃取物及/或自該咸豐草萃取物分離出之一活性化合物；在一實施例中，該組合物可用於降低有需要之目標動物其脂肪細胞的大小及/或脂肪細胞中的脂肪堆積；在一實施例中，該組合物進一步包含動物飼料；本發明另提出一種聚乙炔化合物用於製備一目標動物所需之治療肥胖、降低體重或減少體重增加及/或增加肌肉組織或肌肉含量的醫藥組合物之用途；在一實施例中，該聚乙炔化合物為聚多炔糖苷。
