Archaeobotanical evidence of the use of medicinal cannabis in a secular context unearthed from South China

Ethnopharmacological relevance: As one of the first plants used by ancient people, cannabis has been used for medicinal purposes for thousands of years. The long history of medicinal cannabis use contrasts with the paucity of archaeobotanical records. Moreover, physical evidence of medicinal cannabis use in a secular context is much rarer than evidence of medicinal cannabis use in religious or ritual activities, which impedes our understanding of the history of medicinal cannabis use.

Aim of the study: This study aims to provide archeobotanical evidence of medicinal cannabis use and analyse the specific medicinal usage of cannabis in a secular context in ancient times.

Materials and methods: Plant remains were collected from the Laoguanshan Cemetery of the Han Dynasty in Chengdu, South China, with the archaeological flotation process and were identified based on morphological and anatomical characteristics. The examination of the medicinal significance of the remains relied on the investigation of the documentation on unearthed medical bamboo slips, the diseases of the tomb occupants, the cemetery’s cultural background and Chinese historical records.

Results: The botanical remains were accurately identified as cannabis. More than 120 thousand fruits were found, which represents the largest amount of cannabis fruit remains that have been statistically analysed from any cemetery in the world thus far. The cannabis fruits are suspected to have been used for medical purposes in a secular context and were most likely used to stop severe bleeding of the uterus and treat lumbago and/or arthralgia.

Conclusions: The cannabis fruit remains reported here likely represent the first physical evidence of medicinal cannabis use for the treatment of metrorrhagia, severe lumbago, and/or arthralgia. This study emphasizes the importance of the evidence of the diseases suffered by the occupants of the tomb in determining the medicinal use of cannabis in a secular context and contributes to a comprehensive understanding of the ancient history of medicinal cannabis.