Purpose: This study investigates the effect of the ethanolic extract of Justicia secunda (Blood root) on the vaginal opening and oestrous cycle of female wistar rats. Methodology: Thirty (30) female wistar rats of 18-33g average weight was used. They were divided into six groups of five animals each. Group A received distilled water while animals in group B-F received 250, 300, 350, 400 and 450mg/body weight (kg) respectively of the ethanolic extract of the plant. Monitoring of the onset and completion of vaginal opening was done and the estrous cycle was also monitored throughout 3 weeks of extract administration. Early onset of vagina opening was seen in the treated group compared to the control. The oestrous cycle showed irregularities when compared to the control data were expressed as means ± standard error of mean and analyzed by analysis of variance (ANOVA). Findings: This result showed that the plant extract causes an irregular oestrous cycle and precocious pubertal onset in female wistar rats. Unique contribution to theory, practice and policy: The plant extract of Justicia secunda likely to induce precocious puberty in young female wistar rats and irregular cyclicity in the oestrous cycle. This implies that Justicia secunda is likely to have contraceptive properties.