In order to analyse the role of hypercarotenemia in amenorrhoea, we have studied the ovarian function of 20 patients presenting with hypercarotenemia (serum carotene greater than 5 mumol/l). 12 of these were complaining of secondary amenorrhoea (group I), 7 with a normal weight (group I A) and 5 with a weight below 85% of ideal weight (group I B). Another group of 8 patients had normal menstrual cycles and a body weight within normal limits (group II). Group I presented an ovarian insufficiency of hypothalamic origin with an increase in the FSH/LH ratio. The patients in group I A although of normal weight differed from group II by a history of important weight variations, strenuous sports activity and an essentially vegetarian diet, the most likely reason for their hypercarotenemia. The high carotene levels however do not seem to be directly responsible for the amenorrhoea, in view of the normal menstrual cycles of the patients in group II. Hypercarotenemia can be considered as a biologic marker of weight loss with fat mobilisation and low T3 levels. It can also be due to a vegetarian diet. The latter may be an aetiological factor in anovulation by increasing faecal excretion of oestrogens and thus decreasing blood levels of oestradiol particularly when associated with other compounding factors such as excessive physical activity, loss of weight or affective problems.