This study was designed to investigate the effect of consumption of leaf extract of Vernonia amygdalina during lactation on serum prolactin level. Twenty-four (24) healthy female wistar rats weighing between 150-180g were used for this study. At day 1 of delivery, the animals were divided into 4 groups labeled A – D with six (6) dams in each group. Group A served as control group and received distilled water only. Groups B – D received 100, 250 and 500mg/kg of aqueous leaf extract of V. amygdalina respectively from day 1 of lactation to day 21 via oral route. Blood samples were then collected on day 22 through cardiac puncture and the serum prolactin level was evaluated. Result showed no significant increase (P?0.05) in serum prolactin level in test groups B and C when compared with the control group whereas, group D showed significant increase (P<0.05) in prolactin level when compared with control group. This study supports the use of V. amygdalina in traditional medicine to increase milk production among lactating mothers.