The duruo plant (Pollia japonica), woodblock print coloured by hand. Shunzhi reign period of the Qing dynasty.
The root and stem of duruo can be made into a drug, considered effective for replenishing kidney Qi and treating conditions such as back pain and injuries from knocks and falls.
In Chapter 14 of Bencao gangmu (Systematic Materia Medica), Li Shizhen writes: 'Duruo belongs to Shen Nong's superior (shang) category. It cures various symptoms of foot shaoyin and foot taiyang.' In this quotation, 'Shen Nong' refers to Shen Nong bencao jing (Shen Nong's Pharmacopoeia), a compilation variously dated between the Eastern Han (25-220 CE) and Warring States (475-221 BCE) periods, and possibly containing still earlier material. It lists 365 drugs, divided into three classes: superior, standard and inferior (shang, zhong, xia). 'Foot shaoyin' indicates the kidney channel of foot shaoyin and 'foot taiyang' the bladder channel of foot taiyang.
