Bufalin

Bufalin, is a cardiotonic steroid originally isolated from the Chinese toad venom. It is a component found in many Chinese traditional medicine.
Usage.
Bufalin has an "in vitro" antitumor effects against various malignancies, including hepatocellular and lung carcinoma.
However, as with other bufadienolides, its use is hampered by its cardiotoxicity.