Castor oil is a triglyceride derived from Ricinus communis and has been frequently used in antidiarrhea bioassays on laboratory animals. It has been used to study the effects on rat lens conditions. Castor oil has also been used as a test reagent in the rat model of castor oil-induced diarrhoea to study the dose-response relationship and mechanism of action of Saccharomyces boulardii.