Antacids

An antacid is a substance that neutralizes stomach acidity, which can cause indigestion or heartburn. Among the given options, only Zantac is classified as an antacid. Zantac's generic name is Ranitidine, which works by reducing stomach acid production, providing relief from the symptoms associated with excess acidity.

Aspirin is primarily used as a pain reliever and anti-inflammatory, Equanil is a tranquilizer, and Noradrenaline is a neurotransmitter involved in the body's fight or flight response.

Therefore, the correct answer is: Zantac