Background: Breastfeeding is the best food for infants. Prolactin is combined with the corresponding receptors on the alveoli that produce milk, and milk production begins. We aimed to review the effect of fennel and black seed on breast milk, prolactin levels and anthropometric index in human and animal samples. Materials and Methods: After selecting the keywords related to the research question, searching of the online databases (Medline, EMBASE, Scopus, Web of Science, SID and Magiran) were done. After reviewing the retrieved studies based on the title, abstract and full text, and related articles were selected according to the inclusion criteria. Results: Ten studies were included into review. One study indicated the arousal serum levels of prolactin in lactating mothers using fennel. Four studies showed the fennel as alone or embodied in the herbal tea can increase breast milk. In contrast to the above four studies, a combination of fennel, anise, cumin, dill, parsley and fennel flower had no effect on breast milk volume and neonate weight gain.Two studies inspected the effects of fennel in animal studies. Although 140 and 280 μL doses of fennel have significantly increased prolactin in comparison with 35 and 70 μL g doses, this increment is not sufficient to increase breast milk and, subsequently, to elevate neonates weight with fennel to dairy goats have enhancement and reduction effect, respectively on performance and negative energy balance in early lactation. In another study, black seed improved milk production in cows, while it did not change composition of milk and prolactin. Conclusion: Based on the results, fennel is recommended to increase breast milk, prolactin levels in lactating women.