While there have been claims of weight loss with castor oil because of its strong laxative effects, it is possibly unsafe to take over extended periods of time or in large doses. It can lead to negative and dangerous side effects, such as abdominal cramps, nausea and feelings of weakness.
Castor oil can also lead to excessive loss of fluids and potassium, particularly in daily doses of 15 to 60 milliliters over the course of a week or more.
While castor oil is often used by midwives to induce labor in pregnant women, it is not recommended for pregnant women to attempt this themselves. It is also unsafe for pregnant women to use castor oil earlier in their pregnancy.