On the Belgica expedition (1897-1899), Dr F.A. Cook described a disease that he called 'polar anaemia' and on this expedition it affected most of the expedition members and caused one death. The symptoms were shortness of breath, abnormalities of the pulse and oedema (swelling of the legs) and the disease was clearly cardiac failure. During the heroic age of Antarctic exploration a similar disease affected at least eight other expeditions causing five other deaths. This disease was very similar (and probably identical) to a disease affecting (mostly) Scandinavian seamen and called 'ship beri-beri'. Both diseases were almost certainly what is now called wet beri-beri due to thiamine (vitamin B1) deficiency though most sufferers were probably also vitamin C deficient and some may have had both beri-beri and scurvy. It may have been exacerbated by invalid diets. This paper describes the disease and how it was considered and treated at the time.