Though medical consequences of war attract attention, the health consequences of the prisoner-of-war (POW) experience are poorly researched and appreciated. The imprisonment of Allied military personnel by the Japanese during the World War II provides an especially dramatic POW scenario in terms of deprivation, malnutrition and exposure to tropical diseases. Though predominantly British, these POWs also included troops from Australia, Holland and North America. Imprisonment took place in various locations in Southeast Asia and the Far East for a 3.5-year period between 1942 and 1945. Nutritional deficiency syndromes, dysentery, malaria, tropical ulcers and cholera were major health problems; and supplies of drugs and medical equipment were scarce. There have been limited mortality studies on ex-Far East prisoners (FEPOWs) since repatriation, but these suggest an early (up to 10 years post-release) excess mortality due to tuberculosis, suicides and cirrhosis (probably related to hepatitis B exposure during imprisonment). In terms of morbidity, the commonest has been a psychiatric syndrome which would now be recognized as post-traumatic stress disorder--present in at least one-third of FEPOWs and frequently presenting decades later. Peptic ulceration, osteoarthritis and hearing impairment also appear to occur more frequently. In addition, certain tropical diseases have persisted in these survivors--notably infections with the nematode worm Strongyloides stercoralis. Studies 30 years or more after release have shown overall infection rates of 15%. Chronic strongyloidiasis of this type frequently causes a linear urticarial 'larva currens' rash, but can potentially lead to fatal hyperinfection if immunity is suppressed. Finally, about 5% of FEPOW survivors have chronic nutritional neuropathic syndromes--usually optic atrophy or sensory peripheral neuropathy (often painful). The World War II FEPOW experience was a unique, though often tragic, accidental experiment into the longer term effects of under nutrition and untreated exotic disease. Investigation of the survivors has provided unique insights into the medical outcome of deprivation in tropical environments.