The parotoid gland is an external skin gland on the back, neck, and shoulder of toads and some frogs and salamanders. It secretes a milky alkaloid substance to deter predators. The substance produced acts as a neurotoxin.
Parotoid glands are sometimes said to be wart-like in appearance, though warts are abnormal growths caused by viral infections while parotoid glands are normal, healthy parts of the animals that bear them. The vague similarity in appearance, however, is the reason behind the old wives' tale that touching a toad causes warts.