Castor oil is a safe and effective home remedy for constipation when used according to the directions on the bottle. It can be so effective in purging the intestinal tract, that days will pass before normal intestinal function resumes. The use of castor oil for constipation is possible because it stimulates the walls of the small and large intestines, but it should be used only on a short-term basis, because long-term use can make gastric distress worse. The oil has potential side effects, and it is not recommended for use by nursing or pregnant women because of potential harm to the child.
The castor bean from which this oil is derived contains ricin, one of the most potent poisons known to man, with as little as 1 milligram being a fatal dose for an adult male. Commercial production of castor oil removes the ricin. When using castor oil for constipation, people must consider that the oil can produce pelvic congestion, that it might induce abortions, and that the oil can be carried through milk glands to nursing infants. The fatal dose of castor oil is unknown, but is presumed to be quite large. Persons who abuse this product can experience issues such as dehydration and electrolyte imbalances caused by the oil's tendency to decrease water absorption through the intestinal wall.
In ancient Egypt, it was common to use castor oil for constipation. The castor plant is a native of east Africa and was known to this civilization. Since then, its use has spread worldwide, and it has become a common treatment for a number of other conditions. Castor oil also is used as a flavor enhancer in food production and as a lubricant in many industrial uses. In the early days of the United States, castor oil was mixed with alcohol and sold as a remedy for everything from constipation to arthritis, although research has shown that it has no measurable effect on arthritis.