The subsequent course of 173 women with severe congestive heart failure hospitalized within 6 months of delivery has been analyzed after 4 to 7 year follow-up periods. Forty-seven normotensive women and 50 women hypertensive only during the initial 48 hours have little long term morbidity. Thirty-six women with hypertension initially improved, but many are now showing enlarging cardiac silhouettes. Morbidity is increasing in this group. A similar, less severe pattern is developing in 36 women with intermittent hypertension. The uniquely high incidence of this condition in Zaria is associated with several locale factors. These Hausa-Fulani women eat large quantities of a local lake salt, kanwa, for 40 days postpartum. The syndrome is markedly more common in the hot rainy season, when evaporative water loss is less, than in the dry season. The first postpartum days are spent confined to bed in a small heated room. Once or twice daily the new mother is given hot baths with branches which have been dipped in boiling water. The combination of excessive sodium intake and diminished evaporative water excretion seems to precipitate failure in both normotensive and hypertensive patients.