Chan Su

English Name: toad venom, toad cake, cake of toad skin secretion

Pharmaceutical Name: Venenum Bufonis

Medica Category: Substances for Topical Application

Properties: Chan Su enters the Heart channel; it is acrid and sweet in nature, warm in temperature, and considered toxic according to TCM theory.

What is Chan Su?:

The Chinese Herb Chan Su is derived from the venomous secretions of the Asiatic giant toad (Bufo bufo gargarizans Cantor) and the Asiatic common toad (Bufo bufo melanostictus Schneider). These secretions are milked from the venom glands of these two species of toad and dried into cakes for use as medicine.

Traditional Chinese Medicine (TCM) Therapeutic Actions of Chan Su:

Chan Su relieves toxicity, reduces swelling, and alleviates pain. It can be used clinically to address dermatological disorders with heat and swelling (such as deep-rooted boils, carbuncles, and abscesses), toothache, and selling and pain in the throat.

Chan Su expels dampness associated with summer-heat and opens the orifices to awaken the shen (spirit) to address abdominal pain, vomiting, and diarrhea. In severe cases, it can be used like smelling salts to restore consciousness.

–safety/clinical notes:

General comments about TCM substances for topical application: these substances are categorized differently because many of them are toxic and so should not be used internally; nor should they be used for prolonged periods or at large dosages. This word of caution extends to using these substances over damaged or broken skin, or near sensory orifices through which they can be absorbed and do damage to sensitive/specialized tissues and mucosa. Furthermore, many of these substances are no longer used in TCM and have been added to this glossary for informational and academic purposes.

Contraindicated during pregnancy.

Use with extreme caution internally (internal dosage is 15-30 mg. for oral use) and following precise instructions. Overdose may show adverse reactions within a half hour to two hours after the fact and is marked by severe distress in the gastrointestinal and cardiovascular systems. Various detox methods are mentioned in Chen & Chen (p. 1052) for mild overdose.

Avoid contact with the eyes (use a saline wash or rinse with juice of Zi Cao Gan (lithospermum root)) in cases of contact with eyes.