Poison or cure? Traditional Chinese Medicine shows that context can make all the difference – UB Now: News and views for UB professor and staff



By Yan LIU

Assistant Professor of History

Reprinted from The Conversation

Posted August 31, 2021

Portrait of UB medical historian Yan Liu.

Poisons today usually evoke notions of evil and danger – the opposite of healing drugs. Yet traditional Chinese medicine, practiced for over two millennia, used a large number of poisons to treat various diseases. Chinese doctors knew that what makes a drug therapeutic is not just its active ingredient, it depends on how you use it.

Biomedical researchers skeptical of the safety and effectiveness of traditional Chinese medicine might not be surprised that Chinese doctors historically prescribed poisons. Some believe that the drugs used in traditional Chinese medicine often contain hidden toxic ingredients that are harmful to health.

But this blurred border between poison and medicine is not unique to traditional Chinese medicine. Chemotherapy uses toxic drugs to treat cancer. And the opioid epidemic in the United States offers a thought-provoking reminder of how a class of drugs approved by the FDA and used to treat chronic pain have turned into deadly poisons due to improper administration. Conversely, some psychedelics deemed illegal today have sparked new interest in the medical community as potential treatments for anxiety, drug addiction, and depression.

I am a medical historian who has examined the therapeutic use of poisons in Chinese medicine in my last book. Based on my research, I believe that Chinese physicians in the past recognized the healing ability of poisons while being fully aware of their potential for destruction. Understanding this practice forces modern biomedicine to reconsider how “medicine” is defined today.

What is an active principle?

The debate over the safety and effectiveness of traditional Chinese medicine often centers on the active ingredient in a drug. The United States Food and Drug Administration defines an active ingredient as “any component which provides pharmacological activity or other direct effect in the diagnosis, cure, alleviation, treatment or prevention of disease, or for affect the structure or any function of the body of humans or animals.

In other words, the active ingredient is a specific chemical that is considered to be the essence of a drug. Because it bears the responsibility of curing a target disease, it is used as the gold standard for evaluating the usefulness of a drug in modern pharmacy.

It is useful to identify active ingredients in drug discovery, including those in traditional Chinese medicine. Scientist Tu Youyou won the 2015 Nobel Prize in Physiology or Medicine for isolating artemisinin, an antimalarial drug, from a plant used in traditional Chinese medicine. Likewise, medical researcher Zhang Tingdong and his team identified arsenic trioxide as an effective treatment for leukemia by studying drug formulas in traditional Chinese medicine.

Despite these success stories, reducing a drug to a single molecule is quite limited. This reductionist approach ignores the context in which a drug is used, which plays a crucial role in its end effects. To appreciate this perspective, it is necessary to go back in history to see how poisons were understood and used in premodern China.

Poisons in Traditional Chinese Medicine

The Chinese word for poison is “du” (毒). Contrary to its negative meaning today, ancient texts written 2,000 years ago used the word to denote potency, or the ability to both harm and heal. There was no categorical distinction between poisons and non-poisons in traditional Chinese medicine – they acted on a continuum defined by the level of potency.

The double potential of poisons laid the foundation for their use in medicine. Chinese doctors have strategically deployed powerful poisons to cure everything from blood clots to abdominal pain to epidemic illnesses. For example, aconite (“fuzi” 附子), a very poisonous plant cultivated in southwest China, was one of the most prescribed drugs in medieval times. Mercury was another poison used regularly in medicine and alchemy to kill worms and prolong life. Overall, poisons consistently made up around 20% of the ever-expanding Chinese Pharmacopoeia drugs throughout the Imperial Era, due to their crucial role in healing.

One of the ways Chinese doctors used poisons to heal was the principle of using poison to attack the poison (“gong yi” 以毒攻毒). In their eyes, these powerful substances could target and eliminate specific disease entities like worms inside the body. They believed that the strong sensations induced by the poisons marked a process of cleansing the body from its harmful burdens.

The context in which a drug is used is important

In the past, Chinese doctors did not look for an active ingredient that defined the usefulness of a given substance. On the contrary, they considered the effect of each drug to be very malleable. There is no better example of this thinking than the medical use of poisons.

Chinese doctors were well aware of how the effect of a poison varied greatly depending on how it was prepared and administered. As a result, they developed a variety of methods – such as controlling dosage, mixing with other ingredients, and other drug processing techniques – to lessen the potency of a poison while maintaining its effectiveness.

Chinese doctors also knew that poisons worked differently from person to person. The same medicine can have different effects depending on the sex, age, background, emotional state and lifestyle of the patient. For example, the eminent 7th century physician Sun Simiao (孫思邈) offered specific remedies for women and the elderly.

The use of a poison outside its prescription has often proved fatal. For example, five stone powder, or “Wushi San” (五 石 散), a psychedelic drug containing arsenic, was one of the most popular medicines in medieval China. Despite the medical recommendation that it should only be used as a last resort to treat emergencies, many at the time consumed it regularly to invigorate their bodies and brighten their minds. Unsurprisingly, this misuse has resulted in many deaths. Beyond its restricted use, a poison could easily kill.

Beyond the active ingredient

The paradox of healing with poisons in traditional Chinese medicine reveals a key message: there is no essential, absolute or immutable core that characterizes a medicine. Instead, the effect of a given drug is always relational it depends on how the medicine is used, how it interacts with a particular organism, and its expected effects.

Drugs are fluid substances which defy any stable categorization. Going beyond the biomedical standard for the active ingredient could help doctors and researchers pay more attention to the context in which the drugs are used. This will allow for a more nuanced understanding of healing.

Ultimately, a drug is not limited to its active ingredient. The poisons in traditional Chinese medicine, I hope, teach a compelling lesson.

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