The laser Doppler flowmeter (LDF), which measures changes in cutaneous blood flow, and the transcutaneous oxygen electrode which measures cutaneous perfusion, were used to study reflex changes in the microcirculation of the shoulder in 38 patients with frozen shoulder and 10 normal controls. In all controls and 22 patients with frozen shoulder, a normal LDF response to inspiration/expiration was observed. In 16 patients with frozen shoulder, LDF responses were either unilaterally or bilaterally absent. Comparison between the two patient groups showed a significant association (chi 2 = 6.43, P less than 0.02) between abnormality of response and the persistence of pain. TcPO2 was in the normal range in all patients and controls. These findings suggest that the LDF together with the TcPO2 may be a useful method of studying the skin microcirculation over the shoulder.