Toad (Chanchu): Anticancer Effects and Side Effects

The toad, also called laihama, is the whole body of Bufo gargarizans (Chinese large toad) or Bufo melanostictus (black-spectacled toad) of the Bufonidae family, found everywhere in China. It dwells in moist grass and is common at night or after rain, feeding on various harmful insects and other small animals. The toad is a commonly used Chinese herb with the effects of reducing swelling and stopping pain, and resolving toxins and turbidity. It treats carbuncles and furuncles, swollen painful throat, wind- and tooth-worm toothache, swollen rotting gums, and sha-syndrome abdominal pain. Cinobufacin (Huachansu), an anticancer drug, is a biological medicine extracted from the Chinese large toad, used to treat mid-to-late-stage cancer and hepatitis B.

The whole body and internal organs of the toad can all be used medicinally: the toad head, toad tongue, toad liver, toad gall, toad skin film (chanyi, the outermost thin skin), and toad skin (chanpi, the dried product after removing the internal organs, also called ganchan or zhiganchan). Chan su (toad-cake venom) extracted from the toad is an even more precious Chinese herb, mostly used to make patent medicines such as Liushen Wan. Clinically the most commonly used are toad skin (ganchan) and chansu.

Chansu is processed from a white secretion scraped from the toad's parotoid gland. After scraping, the toad may be released onto clean land or into a clean vessel; it recovers within a few days. But never release the toad into water or contaminated areas after scraping, as this easily causes inflammation of the parotoid gland and kills the toad.

All toad products have anticancer effects, but all are also toxic; chansu is especially toxic. Bufalin in chansu has a specific blocking effect on the proliferation of human cancer cells. The anticancer mechanism of bufalin is mainly through intracellular messenger systems, reducing topoisomerase and thereby inducing apoptosis. By changing the expression of apoptosis-related genes, bufalin can drive the differentiation and apoptosis of various human tumor cell lines and can induce human monocytic leukemia THP11 cells to differentiate into macrophage-like cells. Chansu is generally applied externally to the affected area (not on the eyes), or taken internally in pills or powders at 0.015-0.03 g each time; it should not be taken in excess. Overdosing on chansu can cause poisoning. Chansu poisoning reactions include numb lips, upper abdominal discomfort, nausea and vomiting, dizziness and blurred vision, chest oppression and palpitations, arrhythmia, profuse sweating, drowsiness and coma, and even convulsions and death.

Cinobufotalin (Huachansu) is a water-soluble preparation extracted from the whole skin of the Chinese large toad. It can inhibit the growth of mouse sarcoma S180, mouse solid liver cancer HepS, and mouse reticulocytoma L2. Cinobufotalin is relatively less toxic, but overdosing can still kill the patient. Toad skin has a blocking effect on mouse forestomach cancer and precancerous lesions, induces apoptosis in renal cancer cells GRC-1, promotes Fas expression, and inhibits FasL and bcl-2 expression. The poisoning reactions of cinobufotalin and toad skin are basically similar to those of chansu.

Folk people often catch toads themselves to treat cancer, but there are frequent reports of deaths from self-administered toad poisoning. The main causes of toad poisoning are overdose or overly long use. Moreover, because of individual variation, some patients can experience severe side effects from a single small dose of toad products. I once saw a female patient who, after adding 2 g of dried toad skin to a decoction, developed profuse sweating, vomiting, and diarrhea. So when using toad products in cancer patients, safety must be ensured.

The clinical dose of the patent medicine cinobufotalin is very small, generally only 1/600 to 1/500 of its LD50; this dose is very safe. Even so, clinicians using cinobufotalin must closely observe the patient's reactions and instruct the patient to have periodic liver and kidney function checks.

For chansu or cinobufotalin poisoning, seek medical attention promptly. Generally the following measures are needed: 1. gastric lavage and catharsis; 2. intravenous atropine injection; 3. central nervous stimulant injection; 4. oral or injectable antiarrhythmic drugs; 5. treatment with patent-medicine injections such as Shengmai Injection or Shenfu Injection.

Toad products smell awful, extremely fishy and foul, so I do not recommend using toad alone. I often combine toad with musk (Shexiang) and clove (Dingxiang), on the one hand to enhance the anticancer effect and on the other to offset the foul odor of chansu. Even so, patients still frequently report side effects such as nausea, vomiting, and rash after taking the medicine. An elderly Chinese-medicine physician I know often adds sesame oil to dried-toad powder and makes it into pills for patients, also to offset the foul smell of dried toad.

The daily amount of dried toad and toad skin film should not exceed 3 g, and the daily amount of chansu should not exceed 0.1 g. Toad skin film on the market is expensive, but based on my many years of clinical observation, its clinical efficacy has no great advantage over the much cheaper dried toad, and its side effects are basically comparable; so I do not recommend that patients use the expensive toad skin film.