The Chinese tradition of using toxic heavy metals in elixirs of immortality has historical parallels in Ayurvedic medicine. Rasa shastra is the practice of adding metals and minerals to herbal medicines, rasayana is an alchemical tradition that used mercury and cinnabar for lengthening lifespan, raseśvara is a tradition that advocated the use of mercury to make the body immortal, and samskara is a process said to detoxify heavy metals and toxic herbs.
The historians of Chinese science Joseph Needham and Ho Peng-Yoke wrote a seminal article about poisonous alchemical elixirs. Based upon early Chinese descriptions of elixir poisoning, they decisively demonstrated a close correspondence with the known medical symptoms of mercury poisoning, lead poisoning, and arsenic poisoning. Compare the historical descriptions of Jin Emperor Ai (d. 365) who "no longer knew what was going on around him" and Tang Emperor Wuzong (d. 846) who was "very irritable, losing all normal self-control in joy or anger ... he could not speak for ten days at a time" with the distinctive psychological effects of mercury poisoning: progressing from "abnormal irritability to idiotic, melancholic, or manic conditions". Needham and his collaborators further discussed elixir poisoning in the Science and Civilisation in China series.
Although Chinese elixir poisoning may lead some to dismiss Chinese alchemy as another example of human follies in history, Ho Peng-Yoke and F. Peter Lisowski note its positive aspect upon Chinese medicine. The caution given to elixir poisoning later led Chinese alchemy to "shade imperceptibly" into iatrochemistry, the preparation of medicine by chemical methods, "in other words chemotherapy".
A recent study found that Chinese emperors lived comparatively short lives, with a mean age at death of emperors at 41.3, which was significantly lower than that of Buddhist monks at 66.9 and traditional Chinese doctors at 75.1. Causes of imperial death were natural disease (66.4%), homicide (28.2%), drug toxicity (3.3%), and suicide (2.1%). Homicide resulted in a significantly lower age of death (mean age 31.1) than disease (45.6), suicide (38.8), or drug toxicity (43.1, mentioning Qin Shi Huang taking mercury pills of immortality). Lifestyles seem to have been a determining factor, and 93.2% of the emperors studied were overindulgent in drinking alcohol, sexual activity, or both. The study does not refer to the Chinese belief that the arsenic sulphides realgar and orpiment, frequently used in immortality elixirs, had aphrodisiac properties.