Chamomile is a rich source of phytoestrogens; these compounds have antioxidant, anticancer. In this study, the effects of chamomile on growing oocytes in immature female gourami fish were examined. Thus 60 immature female gourami fish with an average weight of 2-3 g of 6-treated group were analyzed. Treatments in a completely randomized experimental design with a dose of chamomile (10-20-30-50 mg/kg fish) along with control (no injection) and ethanol control (solvent injection) and with three replicates were tested. The fish adaptation to the environment lasted 3 days. The extract injections were done for 20 days, in 10 periods, every other day. In order to histological study, three days after end of the experiment, the ovarian tissue was removed and weighed, tissue processing and staining steps done with hematoxylin- eosin. At last the histological structure of the ovaries and the average percentage of treated fish gonadal indices were compared with the control group. According to our results of gonadal index, there was no significant difference between the control groups with receiving Ethanol (p>0.05). Histological results showed that increasing the dose of chamomile extract accelerate oocyte maturation in three spot gourami. This is the fourth treatment (dose, mg / kg 50) to show its obvious. The difference between oocyte diameter was observed with increasing doses of Chamomile and in comparison with the control group, the difference was significant (p <0.05). Histological results showed that increasing the dose of Chamomile accelerate oocyte maturation in three spot gourami
