Serum concentrations of copper (S-Cu), zinc (S-Zn) and selenium (S-Se) were measured in 34 apparently healthy male prisoners of war immediately on release from a detention camp, and 85 healthy male subjects of comparable age and body mass index who had not been in a war combat zone. The results expressed as median and range were: 1138 (877-1337) micrograms/L of S-Cu, 1087 (514-1260) micrograms/L of S-Zn and 53 (30-100) micrograms/L of S-Se in the former prisoners, and 1149 (869-1487) micrograms/L of S-Cu, 1131 (874-1351) micrograms/L of S-Zn and 65 (45-109) micrograms/L of S-Se in the reference subjects. Significantly lower S-Zn (p < 0.02) and S-Se (p < 10(-5)) were found in the former prisoners compared to the reference subjects, whereas no significant difference between the groups was found for S-Cu (p > 0.80). In the group of former prisoners, a significant positive correlation was found between the S-Zn and S-Se levels (r = 0.40, p < 0.05) and an inverse correlation between S-Zn and body mass index (r = -0.34, p < 0.05), whereas no significant correlation was found of S-Cu, S-Zn or S-Se with age (38 (19-54) years) or duration of imprisonment (130 (126-270) days). As the body mass index of 23.4 (19.7-28.1) kg/m2 and the body mass relative deviation from nomogram of 105 (89-125)% in the group of former prisoners showed no indication of malnutrition, lowered S-Zn and S-Se levels may be ascribed to increased psychological stress induced by conditions during imprisonment.