Variolation Techniques, Medical Explanations, and Dissemination in Late Imperial China

Variolation in China has a long history, yet the method remains underrepresented internationally, having limited recognition of medical rationale and indigenous development. We reviewed medical texts and records from late Imperial China and compared variolation chronology, techniques, and explanatory frameworks used in China versus India. Variolation in China was already in practice no later than the Chenghua–Longqing period of the Ming dynasty (1465–1572 CE), earlier than that reported in other countries. Sources from China described garment/blanket, lymph, and scab-derived inoculum methods for smallpox prevention. Scab-derived inocula, intranasal administration, and repeated passage techniques reflected empirical efforts to improve variolation reliability and reduce risk. Concepts of fetal toxin and seasonal pathogenic qi made variolation intelligible within contemporaneous medicine in China. Records from China predated sources from India and contained more detailed descriptions of variolation practices, supporting indigenous development and highlighting China’s central place in the early history of prophylactic inoculation.