Brain death leads to substantial falls in the plasma levels of cortisol and tri-iodothyronine (T3). These alterations may be responsible for physiological instability in these patients, and impairment in donor organ function. A double-blind study was therefore designed to assess the possible improvement in metabolism and haemodynamic stability in brain-dead organ donors treated with T3 and cortisone. Forty adult brain-dead patients were randomly assigned to two groups, the patients of the treated group were given every hour, or half hour, 2 or 4 micrograms T3 and 100 mg hydrocortisone intravenously, and those of the placebo group normal saline. Both groups of patients received conventional management for brain-dead donors. The main assessment criterion was the haemodynamic course, appreciated by the Pasys, the CVP and the needs in dobutamine; the secondary criterion was the start, or worsening, of a metabolic acidosis, as judged by the pH, the level of arterial bicarbonate, and the needs in sodium bicarbonate. The two groups were comparable for age, sex, aetiology of brain death, the delay between brain death and the start of the experimental protocol, and the duration of this protocol. There were differences between the two groups, which were not statistically significant: improvement in haemodynamic profile (hormone group 9/20 versus placebo group 10/20); worsening in haemodynamic profile (2/20 vs 4/20); increased requirements in dobutamine (2/20 vs 4/20); decreased requirements in inotropic support (15/20 vs 13/20); mean dose of dobutamine (3.1 +/- 4.2 micrograms.kg-1 vs 2.5 +/- 3.8 micrograms.kg-1); metabolic acidosis (5/20 vs 5/20); mean bicarbonate dose (30.0 +/- 67.7 mmol vs 45.0 +/- 74.2 mmol); donors harvested (20/20 vs 18/20).(ABSTRACT TRUNCATED AT 250 WORDS)