Two groups of 15 women with moderately severe post-partum hypotension were assigned at random to receive treatment with either 200 mg dimetophrine or placebo, orally, over a period of 10 days. Systolic blood pressure increased steadily and significantly during the first 5 days of treatment, from 100.0 +/- 1.2 mmHg to 128.0 +/- 1.2 mmHg with dimetophrine; with placebo, the increase from 99.8 +/- 1.1 mmHg to 104.7 +/- 1.1 mmHg was significantly less. Similar results were observed in diastolic blood pressure measurements. Overall, all 15 patients responded to dimetophrine but only 4 spontaneously recovered on placebo. At the same time, heart rate moved towards normal with dimetophrine (from 82.4 +/- 2.0 to 75.5 +/- 1.1 beats/min); with placebo, significantly less recovery was observed (from 79.5 +/- 2.3 to 78.6 +/- 1.5 beats/min). Concomitant with the recovery of perfusion pressure, the associated symptoms (asthenia, paleness, fatigue, dizziness, sweating, headache, vertigo) significantly decreased in intensity, all except vertigo to a significantly greater extent with dimetophrine than with placebo. Subjective tolerance was good in both groups; clinically relevant variations in haematological or haematochemical parameters measured were absent, except for the expected normalization of leucocyte count.