Castor oil, pressed from the seeds of the castor oil plant (Ricinus communis), was the ubiquitous 19th century purgative usually taken by mouth but also formulated in enemas. Although the oil is completely non-toxic, the seeds contain ricin, a highly poisonous substance as deadly as strychnine. In this illustration, castor oil is being bottled by hand at the pharmaceutical factory of Allen & Hanburys in Bethnal Green, East London.

Source: Joseph Hatton. 'An historic pharmacy'. Chemist & Druggist (suppl), 28 January 1893.