Abstract: Aspartame (ASP) consumption has been reported to implicate oxidative stress and antioxidant supplements from plant origin are one of the safest ways of averting their effect in the body. The current study was aimed at ascertaining the ability of aspartame (ASP) to induce oxidative stress in rats as well as assessing the potential of ginger (Zingiber officinale) rhizome and watermelon (Citrullus lanatus) seeds extracts in averting the aspartame induced oxidative stress. This was done using sperm parameters and biochemical assays such as superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, melonaldehyde (MDA), aspartate aminotransferase (AST), alanine aminotransferase and alkaline phosphate (ALP). Forty eight sexually matured male albino rats were divided into six groups (A-F) with eight rats in each group. Group A served as the positive control and received physiological saline. Group B served as the negative control and were administered with 1000 mg kg–1 b.wt., of aspartame (ASP). Rats in group C were administered with 1000 mg kg–1 b.wt., ASP+500 mg kg–1 b.wt., of ginger extracts while rats in group D were administered with 1000 ASP+1000 mg kg–1 b.wt., of ginger extracts. On the other hand, rats in group E received 1000 mg kg–1 b.wt., ASP+500 mg kg–1 b.wt., of watermelon seed extracts while rats in group F received 1000 mg kg–1 b.wt., ASP+1000 mg kg–1 b.wt., of watermelon seed extracts. The result revealed that administration of ASP reduced sperm viability, sperm count and increased sperm head abnormalities significantly (p<0.05) while sperm motility was not affected by ASP administration in the rats. Superoxide dismutase and GPx levels were increased significantly by ginger and watermelon seeds extracts. Although ginger extract reduced more of lipid peroxidation (MDA), watermelon seeds extract increased the activities of SOD, GPx and reduced AST, ALT and ALP in the liver of rats at 1000 mg kg–1 b.wt., than the extract of ginger. Thus, the extracts of these two medicinal plants are possible antioxidant reservoir and may provide reliable solution in averting oxidative stress pathologies.