Copper, zinc and selenium are involved in free radical scavenging. As trace element status is altered after major burns, related free radical scavenging may be decreased: consequently lipid peroxidation, reflected by increased urinary malondialdehyde excretion (MDA), is considerably increased. This preliminary study aimed to investigate the relationship between trace elements and MDA excretion. Sixteen patients aged 34 +/- 9 years (mean +/- s.d.) burned over 37 +/- 11 per cent of body surface, were studied prospectively. Trace element balance studies from days 1 to 7 and serum and urine concentrations on days 10, 15, 20 and 25 were measured. The first 11 patients (groups 1--SBU < 80, and 2--SBU > or = 80) were given standard supplements and the five next patients increased supplements (group 3, SBU > or = 80). The MDA excretion from days 1 to 3 was correlated with burn severity (r = 0.59). The correlations between serum trace element levels after day 3 and MDA were negative: Cu, r = -0.065; Zn, r = -0.52; Se, r = -0.53. In Group 3, MDA excretion after day 3 decreased with increasing cumulative Zn (r = -0.46) and Se intakes (r = -0.57). It can be concluded that the MDA decrease after day 3 was not clearly attributable to the trace element supplements, but the negative trend observed between Zn and Se supplements and decreased MDA excretion requires further studies.