The parotoid gland is an external skin gland

Gland

A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...

 on the back, neck, and shoulder of toad

Toad

A toad is any of a number of species of amphibians in the order Anura characterized by dry, leathery skin , short legs, and snoat-like parotoid glands...

s and some frog

Frog

Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

s and salamander

Salamander

Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...

s. It secretes a milky alkaloid

Alkaloid

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

 substance to deter predators. The substance, bufotoxin

Bufotoxin

Bufotoxins are a family of toxic substances found in the parotoid glands, skin and venom of many toads ; other amphibians; and some plants and mushrooms. The exact composition varies greatly with the specific source of the toxin. It can contain: 5-MeO-DMT, bufagins, bufotalin, bufotenine,...

, acts as a neurotoxin

Neurotoxin

A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...

.

Parotoid glands are sometimes said to be wart

Wart

A wart is generally a small, rough growth, typically on a human’s hands or feet but often other locations, that can resemble a cauliflower or a solid blister. They are caused by a viral infection, specifically by human papillomavirus 2 and 7. There are as many as 10 varieties of warts, the most...

-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 mistaken belief that touching a toad causes warts.