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February 8, 2014

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Home » Feature » Health and Environment

Dangerous ingredients can be beneficial

Quite a few TCM herbs and ingredients are considered toxic, some of them outright poisonous — from scorpion venom and monkshood root to arsenic — but when used properly they can be beneficial, according to TCM experts.

China’s Food and Drug Administration lists 28 poisonous TCM ingredients that must be used with caution and prescribed carefully.

Cannabis is not on the list — it’s hardly in the same “toxic” category with arsenic sulfide.

“In many cases, it is not the herbs that cause problems, but the way we prepare and use them that makes them dangerous,” says Qian Hai, a professor at the Shanghai University of TCM.

Toxic herbs and ingredients are seldom used alone but are combined with other ingredients to ensure synergistic effects while reducing possible side effect, says Qian.

Preparation helps remove undesirable components.

In the case of cannabis, the seeds are the weakest and least toxic parts of the plant and they are generally fried.

Another toxic TCM ingredient, used in combination, is zhu sha (cinnabar 朱砂), which has prescribed to soothe nerves, calm the mind and improve eyesight for more than 2,000 years.

Monkshood root or cao wu (radix aconiti agrestis 草乌) can be poisonous, but is also used to treat rheumatoid arthritis and is contained in the legendary Yunnan Baiyao patent medicine for pain and rheumatism.

Realgar (xiong huang, arsenic sulphide or ruby sulphur 雄黄), arsenic (pi shuang 砒霜) and scorpion venom have also been used to treat cancers in combinations with other TCM ingredients. Realgar is contained in the famous Angong Niuhuang Wan that is used in cases of seizures and other events.

Green dragon (ban xia or pinellia ternata 半夏) is the plant's toxic corm that is contained in Huixiang Zhengqi Solution to aid digestion. If ingested alone, the raw ingredient can cause numbness, vomiting, breathing difficulty and sometimes death.

But prepared properly, it can relieve vomiting.

Arsenic and arsenic sulfide figure in Chinese fiction as killing drugs but they are warm or yang minerals that help relieve asthma and coughing when taken orally. Used externally they can treat ulcers and ringworm.

Arsenic is now used to treat acute myelogenous leukemia.

Mercury (shui yin 水银) is so poisonous that it can only be used externally and is usually prepared with animal fat to treat ringworm, scabies and kill lice.




 

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