Nicotine is a potent parasympathomimetic alkaloid found in the nightshade family of plants. It acts as a nicotinic acetylcholine receptor agonist. It is made in the roots and accumulates in the leaves of the plants. It constitutes approximately 0.6–3.0% of the dry weight of tobacco and is present in the range of 2–7 µg/kg of various edible plants.