The Anti-Cancer Effect and Side Effects of the TCM Herb Qingdai (Indigo Naturalis)
Qingdai (Indigo Naturalis) is the dried powder or cake made by processing the leaves or leafy stems and branches of Strobilanthes cusia (Acanthaceae), Polygonum tinctorium (Polygonaceae), or Isatis indigotica (Brassicaceae). It is produced mainly in Fujian, Yunnan, Jiangsu, Anhui, and Hebei; the best quality comes from Fujian, where it is called "Jian Qingdai."
In ancient times Qingdai was an important dye. Dyeing shops used it to color cloth, and women used it to darken their eyebrows. The ancients often described a woman's eyebrows as "dai eyebrows" precisely because women once drew their brows with Qingdai.
Qingdai is an important anti-cancer TCM herb. Modern pharmacological research found that its anti-cancer active component is indirubin; animal experiments confirmed that indirubin has a moderate inhibitory effect on transplanted tumors. Qingdai is commonly used for chronic myeloid leukemia and also has good efficacy against nasopharyngeal carcinoma, primary liver cancer, and esophageal cancer.
Qingdai comes as a powder or cake and is not decocted. For anti-cancer use, take 9 g of Qingdai powder each time, two to three times daily, mixed into thin porridge or honey. Modern preparations also make it into various oral patent medicines, including capsules and tablets; compound Qingdai capsules and Huangdai Pian are common oncology drugs.
Cancer patients taking Qingdai during radiotherapy or chemotherapy can markedly reduce the toxic reactions caused by radiation and chemotherapy, lower the required radiation dose, and shorten the treatment course.
As a dye, Qingdai colors strongly, so after taking it a patient's stool will become noticeably discolored; there is no need to panic when this happens. When prescribing a formula containing Qingdai, a doctor should warn the patient in advance that the stool will turn very dark, to avoid unnecessary worry.
Qingdai can also be applied externally. It is not a corrosive TCM herb, so external application will not cause surface tumors to ulcerate, making it relatively safe. External application of Qingdai not only relieves pain but also promotes softening, shrinkage, and even resolution of the mass.
Grinding Qingdai, borneol (bingpian), and agarwood (chenxiang) into powder, mixing with honey, placing it at the base of the tongue, and slowly swallowing with saliva can relieve upper digestive-tract obstruction caused by esophageal or cardia cancer.
I sometimes use Dai Ge San (a powder of Qingdai and clam shell powder in a 1:10 ratio) for stubborn cough and hemoptysis in lung-cancer patients, with some effect. In ancient times Dai Ge San was used for cough, sputum, and hemoptysis from liver fire invading the lung.
Traditional TCM holds that Qingdai is bitter, cold, and salty, entering the lung, heart, liver, and stomach meridians. It clears heat and resolves toxin, cools blood and reduces swelling, and clears liver fire. It is used for warm-toxic maculae, sore throat, sores and swelling pain, blood-heat bleeding, and cough with hemoptysis.
For ordinary disease, the usual dose of Qingdai is 1.5–3 g. But for adult cancer patients, 6–9 g per dose is appropriate. For children under 1 year, 0.5–1 g per dose; 2–3 years, up to 2 g; 4–5 years, up to 3 g; 6–9 years, 4–5 g; 10–14 years, up to 6 g; over 14 years, the adult dose.
Qingdai is very hard to dissolve in water, so it works poorly in decoction; it must be taken in powder or pill form.
When Qingdai is used for cancer patients with lung-heat cough and hemoptysis, it should be taken as a powder together with clam shell powder, and combined with other blood-cooling, bleeding-stopping decoctions such as Sanhuang Xiexin Tang to strengthen efficacy.
When Qingdai is used for leukemia patients with purpura, gum bleeding, nosebleed, or hemoptysis, it is often combined with realgar (xionghuang), imperata rhizome (baimaogen), biota twig (cebaiye), gardenia (zhizi), borneol (bingpian), cow bezoar (niuhuang), raw gypsum (shigao), rehmannia (dihuang), and scrophularia (xuanshen)—blood-cooling, bleeding-stopping herbs. The modern preparation Huangdai Pian, made mainly from realgar and Qingdai, is used for leukemia.
Qingdai's main side effect is strong irritation of the digestive tract. Taking Qingdai or its preparations orally often causes excess salivation, diarrhea, abdominal pain, nausea and vomiting, and poor appetite. If these symptoms appear, stop the medicine or combine it with Erchen Wan or Pingwei Wan for symptomatic relief.
Qingdai is not very toxic: it has no fatal side effects and generally does not cause serious liver or kidney damage. Besides its anti-cancer action, it also has some liver-protective effect. It inhibits Staphylococcus aureus, anthrax bacillus, Shigella dysenteriae, and Vibrio cholerae, and it can lower the patient's bilirubin.