Introduction: Several substances were likely to cause the decline in male fertility which could go up to the complete sterility. The aim of this study was to assess the effects of Syzygium aromaticum essential oil on fertility in male rats exposed to manganese. Materials and Methods: Twenty four male rats, 6 months old, were divided into 2 groups; 12 rats in one group received, by oral route, a water containing manganese chloride tetrahydrate (MnCl 2 ·4H 2 O) is at the dose of 4.79 mg·ml −1 for 12 weeks. The group of control male rats received a distilled water in the same conditions. After a period of experimentation, each group was divided into two subgroups of 6 rats which received daily, by intraperitoneal way, a 0.1 mg/kg body weight, of Syzygium aromaticum essential oil. Results: After a chronic exposure, microscopic examination of the testes showed degeneration of the seminiferous tubules and the gremlin cell. Seminal parameters indicated a decrease in the sperm levels (21.3 × 10 6 cells/ml) and a rise of morphological abnormalities (66.1%). However, intraperitoneal administration of essential oil extracted from the flower buds of Syzygium aromaticum, during 3 weeks, to the rats previously intoxicated with Mn, showed a significant rising of sperm concentration (61.2 × 10 6 cells/ml) and a reduction of morphological abnormalities (10.8%). These changes were associated with a significant regeneration of seminiferous tubules and interstitial cells. Conclusion: This study revealed an ameliorative effect of essential oil Syzygium aromaticum in testicular tissue and the sperm quality.