Various materials have been used since ancient times to help immobilise fractures. In this review, we discuss the history and developments of these materials as well as plaster of Paris. There has been a recent trend away from non-operative management of fractures, and skills in the use of plaster of Paris are declining. For the successful treatment of patients, it is important to appreciate how plaster works, how it should be used, and what can go wrong. In this review, we also discuss principles of applications and complications of plaster of Paris.