Severe local and systemic complications may occur after revascularization of extremities exposed to prolonged complete or incomplete ischaemia. These complications may be reduced by controlling the reperfusate and the circumstances of the reperfusion period. Ten adult German domestic pigs were exposed to 6 h of incomplete limb ischaemia by occlusion of the left iliac artery. To simulate the clinical situation of embolectomy, the occlusive snares were released after the ischaemic period in five pigs and normal blood flow developed with systemic pressure (uncontrolled reperfusion). In the other five pigs, a controlled reperfusate was delivered at controlled pressure before establishing normal blood reperfusion (controlled reperfusion). At the end of the observation period (90 min after start of reperfusion), the group with controlled reperfusion had a lower mean(s.e.m.) tissue water content (81·8(0·7) versus 84·3(0·7) per cent, P<0·05, a greater increase in tissue adenosine 5′-triphosphate compared with values at the end of ischaemia (6·2(1·5) versus - 2·5(1·8) μmol per g protein, P<0·03), a higher tissue pH (7·2(0·1) versus 6·8(0·1), P<0·03), a smaller temperature decrease (0·3(0·2) versus 1·2(0·3)°C, P<0·05), lower concentrations of creatine kinase (355·0(87·5) versus 624·4(73·4) units/1, P<0·05) and lactate dehydrogenase (LDH) (369·5(42·5) versus 538·4(39·2 units/1, P<0·03) in the femoral vein blood and lower LDH concentrations (356·5(48·9) versus 546·0(37·8 units/1, P<0·03) in central venous blood. These data indicate that severe local and systemic damage occurs with uncontrolled (normal blood) reperfusion even after incomplete limb ischaemia, and that these changes can be reduced by delivering a controlled reperfusate under controlled conditions.