A review of the literature was carried out in order to identify those mechanisms responsible for hyperplasia of Enterochromaffin-like cells (ECL) undergoing treatment with antisecretory drugs. All gastric acid secretion-inhibiting drugs cause a physiological increase in gastrinemia due to their inhibitory function. ECL hyperplasia is the consequence of the duration of hypergastrinemia. To date no factors responsible for the possible transformation of hyperplasia into carcinoma have yet been identified.