Today, poisons generally conjure up notions of evil and danger – unlike drugs for healing. Yet traditional Chinese medicine, practiced for more than two millennia, used a large number of poisons to treat various illnesses. Chinese doctors knew that what makes a drug therapeutic isn’t 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 have historically prescribed poisons. Some believe that drugs used in traditional Chinese medicine often contain hidden toxic ingredients that are harmful to health.
But this blurred line 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 sobering reminder of how a class of FDA-approved drugs used to treat chronic pain became deadly poisons through misadministration. Conversely, some psychedelics deemed illegal today have sparked new interest in the medical community as potential treatments for anxiety, addiction, and depression.
I am a medical historian who examined the therapeutic use of poisons in Chinese medicine in my recent book. Based on my research, I believe Chinese doctors of the past recognized the healing ability of poisons while being fully aware of their deadly potential. Understanding this practice forces modern biomedicine to reconsider how “medicine” is defined today.
What is an active ingredient?
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 that provides pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or for affect the structure or any function of the human body”. or animals.
In other words, the active ingredient is a specific chemical considered to constitute the essence of a drug. Because it bears the responsibility of curing a target disease, it is used as a gold standard to gauge a drug’s usefulness in the modern pharmacy.
It is useful to identify active ingredients in drug discovery, including those from traditional Chinese medicine. Scientist Tu Youyou won the 2015 Nobel Prize in Physiology or Medicine for isolating the antimalarial drug artemisinin from a plant used in traditional Chinese medicine. In a similar vein, medical researcher Zhang Tingdong and his team identified arsenic trioxide as an effective treatment for leukemia by studying traditional Chinese medicine drug formulations.
Despite these successes, the reduction of a drug to a single molecule is rather limited. This reductionist approach ignores the context in which a drug is used, which plays a crucial role in its final 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). Unlike 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 potency level.
The dual 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 diseases. For example, aconite (“fuzi” 附子), a highly poisonous herb grown in southwestern China, was one of the most commonly prescribed medicines in medieval times. Mercury was another poison regularly used in medicine and alchemy to kill worms and prolong life. Overall, poisons consistently accounted for around 20% of medicines in the ever-expanding Chinese pharmacopoeia throughout the Imperial era, indicating their crucial role in healing.
One of the ways Chinese doctors used poisons for healing was the principle of using poison to attack poison (“yi du gong du” 以毒攻毒). In their view, these potent 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 of its harmful charges.
The context in which a drug is consumed matters
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 highly malleable. No better example illustrates this way of thinking than the medical use of poisons.
Physicians in China were acutely aware of how the effect of a poison varied greatly depending on how it was prepared and administered. As a result, they have developed a variety of methods – such as dosage control, mixing with other ingredients, and other drug processing techniques – to lessen a poison’s potency while preserving its effectiveness.
Chinese doctors also knew that poisons worked differently from person to person. The same medicine can have different effects depending on the gender, age, background, emotional state and lifestyle of the patient. For example, the prominent 7th century physician Sun Simiao (孫思邈) offered remedies specific to women and the elderly.
The use of poison outside of its prescription has often proven fatal. For example, Five-Stone Powder, or “Wushi San” (五石散), a psychedelic drug that contains arsenic, was one of the most popular medicines in medieval China. Despite medical advice to use it only 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 poison healing in traditional Chinese medicine reveals a key message: there is no essential, absolute or immutable core that characterizes a medicine. Instead, the effect of any given drug is always relational – it depends on how the drug is used, how it interacts with a particular body, and its intended effects.
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Drugs are fluid substances that defy stable categorization. Going beyond the biomedical standard of active ingredient could help doctors and researchers pay more attention to the context of drug use. This will allow for a more nuanced understanding of healing.
Ultimately, there is more to a drug than its active ingredient. The poisons of traditional Chinese medicine, I hope, teach a compelling lesson.