A Jamaican chicken pill is a pill that farmers use to increase appetites in chickens and make them larger than their usual size, explains NPR. Although Jamaica allows the pill, many other countries ban its use due to its side effects.
A trend began on the island of Jamaica in the 1990s in which women would take the chicken pill thinking that it would help their bodies develop faster than normal, notes NPR. However, the women who took these pills suffered various side effects, such as numbness and diarrhea. The chicken pill also contains arsenic, which builds up in the body and causes cancer.