Bacterial bulb rots of onion are among the most serious storage diseases that lead to great loss in the yield. In this study, sodium salicylate, ascorbic acid and thiamine hydrochloride were tested as resistance inducers on onion plants grown under in vivo condition to evaluate their potentials in controlling the bacterial rot diseases. The tested inducers were found to be effective in decreasing the bacterial rot incidence in stored onion bulbs. The treatments significantly increased the total phenols and significantly declined lipid peroxidation and the electrolyte leakage in onion bulbs indicating their potentials to induce the natural resistance. Moreover, the inducertreated plants showed an increase in photosynthetic pigments content and foliar growth compared to the untreated control, justifying the role of chemical inducers in improving plant growth. It could be concluded that, the application of some chemicals to induce the intrinsic resistance in plants is a safe and effective tool in controlling plant diseases that can replace and minimize the hazardous effects of chemical pesticides.