Cholera still represents a major public health problem in developing countries, and it is associated with significant morbidity and mortality in spite of the fact that more is known about its epidemiology, pathophysiology, and treatment than is known concerning any other diarrheal illness. During the past 5 years cholera has gained the attention of the scientific community because of three events: the extension of the seventh pandemic of El Tor Vibrio cholerae O1 to South and Central America in 1991; the appearance of a novel non-O1 V. cholerae, referred to as V. choierae O139 or "Bengal" strain in October 1992 in India and Bangladesh; and the explosive epidemic of multiple-resistant V. cholerae O1 El Tor among Rwandan refugees in Zaire in 1994, with the highest mortality ever reported. This report presents data on recent epidemics of cholera, focusing on epidemiologic, clinical, therapeutic, and preventive issues. Lessons learned from these epidemics should help researchers to prevent or control future epidemics. More effective vaccines than are currently available, with broad coverage against new agents, clearly are needed.