Castor oil cannot be considered as the drug of choice for constipation.
Castor oil is not to be taken as self medication.
It should only be taken under medical supervision.
It is not for children below 6 years and for
pregnant women.
Castor oil is taken in a dose of 15 ml (one tablespoon) . It has a very unpleasant taste. So it should be mixed with fruit juice or squash or milk (to make the total volume up to 50ml). It should be taken in the morning. The effect is seen in 2 1/2 to 3 hours. It is effective. But don't take it at night, otherwise the effects will be seen at midnight.
It is contraindicated in any type of pain abdomen or bleeding from the rectum.
In short it is not a good choice for constipation.