Bufadienolide is a chemical compound with steroid structure.

Both bufadienolides and their glycosides are toxic; specifically, they can cause an atrioventricular block, bradycardia (slow heartbeat), ventricular tachycardia (a type of rapid heartbeat), and possibly lethal cardiac arrest.

[1] The term derives from the toad genus Bufo that contains bufadienolide glycosides, the suffix -adien- that refers to the two double bonds in the lactone ring, and the ending -olide that denotes the lactone structure.

Consequently, related structures with only one double bond are called bufenolides,[2] and the saturated equivalent is bufanolide.

This drug article relating to the cardiovascular system is a stub.