Twenty-five women with idiopathic oedema and twenty-five women attending gynaecology clinics were assessed by means of a standardised psychiatric interview, an interview on dietary habits, and a specially designed interview on current health. The patients with idiopathic oedema were significantly more depressed and anxious, with a trend towards widespread neurotic symptoms. There was no evidence that diuretic or laxative abuse is an important aetiological factor. In many patients with idiopathic oedema excessive fluid retention may be related to the neuroendocrine abnormalities associated with psychiatric illness.