原料药（英文：API, Active Pharmaceutical Ingredients），又称活性药物成份，由化学合成、植物提取或者生物技术所制备，但病人无法直接服用的物质，一般再经过添加辅料、加工，制成可直接使用的药物。

目前中国和印度为两个主要原料药生产国。

出口到欧洲的原料药须通过COS/EDMF认证，出口到美国的原料药须通过DMF认证，日韩等国家也有一些类似的认证。

An active ingredient (AI) is the ingredient in a pharmaceutical drug that is biologically active. The similar terms active pharmaceutical ingredient (API) and bulk active are also used in medicine, and the term active substance may be used for natural products. Some medication products may contain more than one active ingredient. The traditional word for the API is pharmacon or pharmakon (from Greek:φάρμακον, adapted from pharmacos) which originally denoted a magical substance or drug.