Terlipressin--a long-acting analogue of vasopressin--has been described to restore blood pressure in patients with catecholamine-resistant septic shock without obvious complications. We administered low-dose terlipressin (a single i.v.-bolus of 0.5 mg) to a patient with severe, hyperdynamic septic shock requiring high dosage of noradrenalin. After terlipressin the dose of noradrenalin could be reduced by 2/3 to obtain the same blood pressure. Two hours after terlipressin, the cardiac index had decreased from 6.2 to 3.3 l min(-1) m(-2) and the concentration of L-lactate in the rectal lumen, as assessed by equilibrium dialysis, increased from 3.6 to 7.2 mmol l(-1). In contrast, the systemic concentration of L-lactate was unaffected around 2.8 mmol l(-1). After 8 h the effect of terlipressin started to decline, and after an additional 12 h the systemic haemodynamics, dose of noradrenalin and concentrations of rectal and systemic L-lactate were the same as prior to the administration of terlipressin. As a strong vasopressor, terlipressin may have further impaired the metabolic dysfunction in the rectal mucosa either directly via vasoconstriction of mucosal vessels or through decreased cardiac output in this patient with noradrenalin-treated septic shock.