The selective venoconstrictor dihydroergotamine (DHE) was given intravenously to 12 women with evidence of pelvic congestion. In 6 the effect of the drug on pelvic veins was observed by pelvic venography. After DHE there was a mean reduction of 35% in the diameter of the pelvic veins measured and the contrast medium cleared rapidly, with a visible reduction in pelvic congestion. In the other 6 women DHE was given during an acute attack of pelvic pain. The effect of the drug on pain relief was assessed by a single-blind crossover trial with intravenous saline as the placebo and by a visual analogue scale to assess the intensity of pain. Pain was significantly lower post-DHE 4 and 8 h and 2 and 4 days after treatment than after placebo. The results confirm a close association between demonstrable pelvic congestion and pelvic pain.