The Origins of Poison in Chinese History
The use of poison as a weapon has deep roots in Chinese history, stretching back to antiquity. Historical records suggest that as early as the Han Dynasty (206 BCE–220 CE), toxic substances were already being employed in political assassinations. One infamous case involved Empress Xu of Emperor Xuan of Han, who was poisoned by the wife of the powerful regent Huo Guang. Similarly, the emperor’s favored official, Zhang Pengzu, fell victim to poisoning at the hands of his own concubine. By the tumultuous transition between the Western and Eastern Han Dynasties, poison had become a favored tool in court intrigues, with figures like Wang Mang accused of using it to eliminate rivals—even facing rebellion over allegations that he poisoned Emperor Ping.
But poison was not confined to the shadows of palace coups. Its use in warfare dates back even further, with the earliest recorded instance occurring in 667 BCE during the Spring and Autumn Period. The Qi army, occupying the territory of Sui, suffered heavy casualties when the locals poisoned their drinking water. The Zuo Zhuan (Commentary of Zuo) later documented another case in 559 BCE, where the Qin state poisoned the upper reaches of the Jing River, leading to mass deaths among the invading Jin troops.
Poison in Warfare: Tactics and Limitations
Despite these early examples, poison was far more prevalent in political assassinations than in large-scale warfare. Statistics from the Wei-Jin and Northern and Southern Dynasties (220–589 CE) reveal at least 58 documented cases of political poisonings, including high-profile incidents like Dong Zhuo’s murder of Empress Dowager He and Liu Yu’s assassinations of Emperors An and Gong of Jin.
Why was poison not more widely used in war? The answer lies in logistics and production. Ancient poisons fell into three categories:
1. Animal-based poisons (e.g., snake venom, scorpion toxin) – Difficult to harvest in large quantities.
2. Plant-based poisons (e.g., aconite, strychnine, and the infamous “instant-death” jianxuefenhou from the Antiaris toxicaria tree) – Regionally limited and hard to mass-produce.
3. Mineral-based poisons (e.g., arsenic trioxide, cinnabar) – Expensive and challenging to refine in bulk.
Without industrial production capabilities, contaminating water sources on a battlefield scale was nearly impossible. Instead, armies often resorted to cruder methods—dumping rotting animal carcasses into rivers to spread disease or coating arrows with feces to induce tetanus.
The Evolution of Poison Weapons
By the medieval period, military strategists began experimenting with more sophisticated poison delivery systems. The Wujing Zongyao (Complete Essentials for the Military Classics), a Song Dynasty (960–1279) military manual, described “poison smoke balls”—gunpowder projectiles laced with wolfsbane, langdu (a toxic herb), and arsenic. These weapons could induce bleeding from the nose and mouth upon inhalation.
Defensive measures also emerged. The same manual outlined protocols for detecting poisoned water sources, reflecting growing awareness of chemical warfare. Soldiers were warned to:
– Avoid suspicious water supplies
– Inspect local environments carefully
– Follow strict procurement rules
The Political Legacy of Poison
While poison’s battlefield role remained limited, its impact on politics was profound. The frequency of poison-related regicides and coups demonstrates how elites weaponized toxic substances to bypass conventional power struggles. The case of Empress Dowager Feng poisoning Emperor Xianwen of Northern Wei illustrates how poison could reshape dynastic succession.
Conclusion: Why Poison Favored the Shadows
Ultimately, three factors restricted poison’s military use:
1. Production bottlenecks – No pre-industrial society could manufacture toxins at scale.
2. Geographical constraints – Many plant toxins were regionally exclusive (e.g., jianxuefenhou grew only in Yunnan).
3. Tactical inefficiency – Open battlefields favored steel over subtlety.
Yet in the corridors of power, where a single cup of wine could alter history, poison remained the silent sovereign of intrigue—a weapon whose legacy endures in both historical records and cultural imagination. From the mythical “zhèn wine” (allegedly made from a nonexistent venomous bird) to the very real arsenic that toppled emperors, toxic substances shaped China’s political landscape far more than its battlefields.