Cysticercosis is caused by the establishment of Taenia solium larvae (cysticerci), mainly in the central nervous system (CNS) and skeletal muscle of humans and pigs, after ingestion of eggs shed in human faeces by the adult tapeworm (see centrepage diagram). Human neurocysticercosis - often a life-threatening disease - is increasingly recognized as a public health problem, especially in developing countries. Clinical incidence of neurocysticercosis can reach 7% in Mexico and 18% in the Ekari population of New Guinea, while prevalence in autopsies ranges from 0.4% to 3.6% in several countries of Latin America, Asia and Africa. Many cases have also been recently reported in the USA, usually in immigrants. In this review, Ana Flisser focuses on the problems of cysticercosis in Mexico, where the disease is now recognized as a priority both in public health and economic terms. Recognition of the problem has been greatly aided in recent years by new developments in diagnosis - especially computed tomography (CT) to diagnose early stages of neurocysticercosis - and by improved drug treatment.