Illustration of 'crab-roe water' (xiehuang shui) from Shiwu bencao (Materia dietetica), a dietetic herbal in four volumes dating from the Ming period (1368-1644). The identity of the author and artists is unknown. It contains entries on over 300 medicinal substances and is illustrated by almost 500 paintings in colour. The illustration depicts the procedure for obtaining crab-roe water. The yellow part of the crab is removed and put in a lacquer vessel, and mixed until it dissolves. The ancients used this liquid to concoct medicines. The text states: Crab-roe water is used to treat epidemic diseases (tianxing), epilepsy (dianxian), erysipelas (dandu), lacquer sores (qi chuang) etc.