With simultaneous application reduces the absorption of fat-soluble vitamins A, D and K.
In doses up to 4 g / day increases the absorption of fat-soluble drugs - the extract of male fern, mebendazole, griseofulvin, probucol.
With simultaneous application with salt laxatives, a strong laxative effect is possible.
M-cholinoblocking agents (atropine sulfate, platyphylline, pirenzepine), antispasmodics (papaverine, drotaverine) weaken the action of castor oil.
Strengthens the action of the agents stimulating the contractile activity of the myometrium (methelergometrin, ergometrine, oxytocin, prostaglandins), up to the threat of rupture of the uterus in childbirth.