Prostaglandin E₁ (PGE1) is a prostaglandin.

The synthetic variant is known pharmaceutically as alprostadil. It is a drug used in the continuous treatment of erectile dysfunction and has vasodilatory properties. Misoprostol is another synthetic prostaglandin E₁ analog used to prevent gastric ulcers when taken on a continuous basis, to treat missed miscarriage, to induce labor, and to induce abortion.