A cholera attack is the result of a very complicated interaction between the host and the bacterium Vibrio cholerae which has a large array of weapons at its disposal, among which the cholera toxin. The disease can cause death by shock at an amazing short term. Therapy is of an astonishing simplicity: replacement of the lost body fluid plus some positive and negative ions is sufficient in most of the cases. Prevention lies mainly in well designed systems of water production and supply and sewage systems. Apart from that effective vaccines are much wanted. The development of these is still going on since the present vaccines are insufficient; they generate too little immunity at the level of the mucous membranes of the small intestine.