The Scottish medical missionary James Henderson (1830 – 1865) received his medical training at Edinburg medical school. After a brief spell of medical practice in Scotland, Henderson joined the London Missionary Society and was sent to China in 1860. Henderson worked at the Missionary Hospital in Shanghai, taking over the position vacated by his predecessors William Lockhart (1811 – 1896) and Benjamin Hobson (1816 – 1873). At the time the Treaties of Tianjin (1858) had consolidated the treaty system, and Shanghai was both growing rapidly and riven by violence. The war between the Qing government and the Taiping was raging.  At the docks fighting erupted frequently between rival migrant workers’ gangs from different provinces. Henderson’s hospital often provided emergency treatment to victims of the violent conflicts. The hospital admitted Chinese patients suffering from leprosy, cholera, madness, opium addiction and numerous other diseases. During his medical career in China Henderson met several important missionary figures and left a substantial amount of writings in the forms of letter, memoir, hospital report and treatise. He was, moreover, one of the first western medical practitioners who wrote systematically on the influence of Chinese climates on European health. I will in the talk situate Henderson’s work in the long tradition of personal hygiene in Western medicine. I will also examine the relationship between British medical studies on tropical hygiene and medical topography and Henderson’s medical thoughts. Lastly, I will discuss Henderson’s studies of the diseases that he encountered and his experimentation with their treatment.