Illustration of 'flower water' (huashui) from Shiwu bencao (Materia dietetica), a dietetic herbal in four volumes dating from the Ming dynasty (1368-1644) © Wellcome Collection, London 

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. This illustration depicts the collection of flower water (huashui), i.e. raindrops and dew obtained from flowers. The text states: Flower water is neutral in thermostatic character and non-poisonous. It is effective in quenching thirst. For long journeys where water is unavailable, one should prepare pellets of flower water, bitter gourd (kugua) and betel; if one eats these, one will never suffer thirst.