Ricinoleic acid is a naturally occurring 12-hydroxy fatty acid. It constitutes about 90% of the fatty acids in castor oil. Ricinoleic acid can serve as a substrate for the synthesis of conjugated linoleic acids. It is considered safe and non-toxic as a food constituent in humans, up to a daily intake of 2.5 grams per day. In high doses, castor oil has a laxative effect.