Background: Rodent repellent substances are chemicals that have taste, odors, or both that will prevent rats from feeding or gnawing. Effects of fresh or fermented clover plant juice were studied as a repellent against both sex black rat, Rattus rattus, under laboratory and stores (fertilizers and equipment stores) conditions in Giza Governorate. Each fresh and fermented clover plant juice mixed with crushed maize at 23.8% (the appropriate concentration) was tested as bait using non and free choice feeding methods. Results: The results revealed that fermented juice was more repellent than fresh juice for rats as it achieved 92.6% repellency comparing with 38.7% for fresh juice after 4 days of treatment. The bodyweight of rats reduced after treated with fermented bait while it increased with fresh bait. The fermented and fresh clover juices were analyzed on Gas Chromatography-Mass Spectrometry (GCMS). The chemical compounds analysis names were: Erythro- 3- bromo -2- pentanol and other compounds while Thero -3- bromo -2- Pentanol compound was found only in fermented juice. The concentrations of the recorded compounds in fermented juice were higher than those in fresh juice. On the other side, the fermented clover plant juice bait achieved 85.7% efficiency against black rat, R. rattus as a repellent in stores after one week of treatment.
Conclusion: The fermented clover plant juice cussed repellent to the rodent.    So, it can be used for protecting stores of different materials (equipment, electric cables and raw materials) from rodent attacks.