Definition: An active ingredient is the component of a medication responsible for the medication’s effect.
Also Known As: therapeutically active ingredient, pharmaceutically active ingredient
Examples:The active ingredient in Zoloft, a prescription medication used to treat depression, is sertraline hydrochloride. The active ingredient in Prilosec, an over-the-counter medication used to treat GERD (heartburn), is omeprazole magnesium. The active ingredient in BJ's Allergy Medicine, an over-the-counter medication used to treat nasal allergies, is diphenhydramine HCL, which is also sold under the brand name Benadryl.