Patients with unilateral renal/ureteral calculosis who had suffered a few painful attacks were examined. In the pain-free period, muscular, subcutaneous and cutaneous sensory thresholds to electrical stimulation were measured in the lumbar region (metamer L1) on both sides: (1) pain thresholds were lower on the affected side with respect to both the contralateral side and control thresholds recorded in normal subjects; (2) the greatest decrease in threshold was in the muscle (even the sensation of sustained contraction was no longer detectable), followed by subcutaneous tissue, and the smallest decrease was in the skin.