Effects of Aloe Barbadensis, a type of Aloe Vera, on reproductive system were investigated during pregnancy. Aloe Vera gel, a commercial and nontherapeutic form of Aloe Barbadensis, was used for this purpose. 3 groups - 1 control and 2 test groups - of female Wistar Albino rats with no birth before were studied. Group I was administered 25 mg (140 mg/kg) of Aloe Barbadensis per day both orally and through gavage. Aloe Barbadensis was inside capsules that contain 500 mg of soybean oil; therefore Group II was administered that 500 mg of soybean oil. Group III were the control group. All three groups were nourished on normal feed and water ad libitum. The substance had been administered for 20 days until the birth. Organs involved in reproductive system were examined on histological bases. Tissue of uterus had a hyperemic view, and vessels were distinct and dilated. Neutrophil leukocyte infiltration was detected on all layers from lamina propria to myometrium. Glands were cystic dilated, and epitel had a hyperplasic view some regions. Vascular increase and hypertrophy on endometrium lumen epitel were observed. Vascular increase and hyperemic form of ovary in the group administered with Aloe Barbadensis was notable. Decreasing of primer follicle's number, increasing of seconder follicle's number and diminishing of seconder follicle's diameter have been occurred in ovary. Aloe Barbadensis administered during pregnancy period did not cause fetal death, growth retardation, abortus or anomaly. The histological changes imply angiogenesis effect of Aloe Barbadensis and an effect like estrogen in uterus and an effect like FSH in ovary. This effect did not damage fetus a dose of 140 mg/kg.