Bufotoxins are a family of toxic steroid lactones or substituted tryptamines of which some may or may not be toxic. They occur in the parotoid glands, skin, and poison of many toads (genus Bufo) and other amphibians, and in some plants and mushrooms. The exact composition varies greatly with the specific source of the toxin. It can contain 5-MeO-DMT, bufagins, bufalin, bufotalin, bufotenin, bufothionine, dehydrobufotenine, epinephrine, norepinephrine, and serotonin. Some authors have also used the term bufotoxin to describe the conjugate of a bufagin with suberylarginine.

The toxic substances found in toads can be divided by chemical structure in two groups:

1. bufadienolides, which are cardiac glycosides (e.g., bufotalin, bufogenin)
2. tryptamine-related substances (e.g., bufotenin)

Toads known to secrete bufotoxin include the following:

• Bufo alvarius
• Bufo americanus
• Bufo arenarum
• Bufo asper
• Bufo blombergi
• Bufo boreas
• Bufo bufo
• Bufo bufo gargarizans
• Sclerophrys gutturalis (syn. Bufo gutturalis)
• Bufo formosus
• Bufo fowleri
• Rhinella marina (formerly Bufo marinus)
• Bufo melanostictus
• Bufo peltocephalus
• Bufo quercicus
• Bufo regularis
• Bufo valliceps
• Bufo viridis
• Bufo vulgaris