This review considers the some of the methods of automatic control which are usable in medicine. The features of each type of control system are explained and the advantages and disadvantages summarised. The author has attempted to maintain a balance between what is possible with the excellence of modern engineering, and what is feasible in the clinical area, and practical when working with patients. The problem of lack of knowledge of an individual patient is emphasised, as is the potential of fuzzy logic methods in the future.