Mecamylamine is a nicotinic antagonist that is well absorbed from the gastrointestinal tract and crosses the blood-brain barrier. Mecamylamine has been used as a ganglionic blocker in treating hypertension, but, like most ganglionic blockers, is more often used now as a research tool.

Mecamylamine is also sometimes used as an anti-addictive drug to help people stop smoking tobacco, and is now more widely used for this application than it is for lowering blood pressure. This effect is thought to be due to it blocking α3β4 nicotinic receptors in the brain.