Abstract Cholera, the dreaded scourge causing death from dehydrating diarrhoea, existed for centuries in South Asia until, in 1817, it broke out along trade routes; since then there have been seven pandemics across all six inhabited continents. Vibrio cholerae is a Gram-negative organism that can be subdivided into over 200 serogroups based on the somatic O antigen, with only serogroups O1 and O139 causing epidemic and pandemic disease. Historically it has killed millions from dehydrating diarrhoea, encouraged the birth of modern epidemiology, the sanitary revolution, and oral rehydration therapy; it persists today as a glaring reminder of poverty and inadequate water/sanitation. Contaminated food (especially undercooked seafood) is the usual route of transmission in developed countries; contaminated water and street food vendors are more common vehicles in less developed countries.