Castor oil is a colorless to yellowish-brown oil from the castor bean. It has a nauseating taste but heavy in vitamins such as Vitamin D. There's no basis in its health benefits, but it was used as a home remedy by adults, such as Mrs. Crutch and Dickie's nurse. Miss Jones also keeps a bottle of it in her desk in Bored Of Education. Mickey Daniels is given a dose when he has his tonsils removed, and later the rest of the gang is threatened with a large bottle to teach them a lesson about faking illness in No Noise. Similarly, Mickey, Jackie Condon, and Joe Cobb get doses after faking "speckled fever" in Circus Fever.