Different doses of aqueous extracts from the leaves of Aloe buettneri, Justicia insularis, Hibiscus macranthus and Dicliptera verticillata, locally used to regulate the menstrual cycle and to treat dysmenorrhea or infertility in women, were given daily to 22 day old rats for 5, 10, 15, 20 and 25 days by gastric intubation. At the end of each experimental period, the weights of ovaries and uteri, levels of uterine and ovarian proteins, ovarian cholesterol and serum oestradiol were evaluated. The results showed a decrease in growth rate of animals treated with 94 mg/kg per day at the end of the experimental period. The ovarian and uterine weights were high in all treated groups especially within the pubertal period (36-41 days old) when compared to the respective controls. During the same period, the parameters analysed showed significant differences in treated rats when compared to the controls. This was seen with ovarian and uterine protein levels, as well as with serum oestradiol whose level was especially high in the groups given 49 or 94 mg/kg per day of the plant extracts (52 and 42%, respectively when compared with the respective controls). A concomitant decrease in ovarian cholesterol was observed in the same treated groups. These results suggested a possible presence of oestrogenic compounds in the plant extracts.