Toads in the family Bufonidae have a region of skin known as "the seat patch", which extends from mid abdomen to the hind legs and is specialized for rapid rehydration.

[9] The taxonomic affinities of I. alvarius remain unclear, but immunologically, it is similarly close to the boreas and valliceps groups.

Normally, 1–3 days after the rain is when toads begin to lay eggs in ponds, slow-moving streams, temporary pools or man-made structures that hold water.

[11] The toad's primary defense system is glands that produce a poison that may be potent enough to kill a grown dog.

[12] These parotoid glands also produce 5-methoxy-dimethyltryptamine (5-MeO-DMT)[13] and bufotenin (which is named after the Bufo genus of toads); both of these chemicals belong to the family of hallucinogenic tryptamines.

[15] After inhalation, the user usually experiences a warm sensation, euphoria, and strong visual and auditory hallucinations, due to 5-MeO-DMT's high affinity for the 5-HT2 and 5-HT1A serotonin receptor subtypes.

[17] In addition to bufotenin, Bufo secretions also contain digoxin-like cardiac glycosides, and ingestion of the poison can be fatal.

[25] Contemporary reports indicate that bufotenin-containing toad toxins have been used as a street drug; that is, as a supposed aphrodisiac,[26] ingested orally in the form of ch’an su,[22] and as a psychedelic, by smoking or orally ingesting Bufo toad secretion or dried Bufo skins.

The use of chan'su and love stone (a related toad toxin preparation used as an aphrodisiac in the West Indies) has resulted in several cases of poisoning and at least one death.

[28] Ken Nelson (under the pseudonym of Albert Most) published a booklet (illustrated by Gail Patterson) titled Bufo alvarius: The Psychedelic Toad of the Sonoran Desert[29][30][31] in 1983 which explained how to extract and smoke the secretions.

Among the notable people who have spoken publicly about their experiences with the psychoactive agents in the poison are boxer Mike Tyson,[32] comedian Chelsea Handler,[33] podcaster Joe Rogan,[34] television personality Christina Haack,[35] and motivational speaker Anthony Robbins.

[36] On October 31, 2022 the United States National Park Service posted a warning on Facebook that people should not handle or lick the toad.

Synthetic forms of the drug that collectors seek in the toad poison are fairly easy to produce and may offset overcollection.