https://www.maximizemarketresearch.com/market-report/active-pharmaceutical-ingredients-market-middle-east/2237/ An active ingredient is that constituent of a pharmaceutical drug that is organically active. The active ingredient was traditionally known as pharmacon meaning magical substance within drugs. Active pharmaceutical ingredients (API) and bulk active are both synonymously used for representing active ingredients. The content of API is dependent on the manufacturers and usually differs from one brand to another. There are certain products that may contain more than one active ingredient.