White rot of onion is still one of the most destructive diseases in Egypt causing significant losses in bulb yield. The causal organism produces abundant amount of sclerotia in the soil and therefore, it has been established in many parts of Egypt particularly in upper and Middle Egypt. Different methods of disease management were applied; however, the disease is still the main problem of onion in Egypt. Plant extracts, i.e. neem and datura, as well as salicylic acid and sodium benzoate antioxidants were tested to control the disease under either greenhouse or field conditions. Obtained results were compared to a fungicidal treatment (Folicur) at different concentrations using the onion (cv. Giza 20). A field experiment was carried out for two seasons (2011 and 2012). Application of plant extracts of neem and datura reduced the rot incidence accompanied by high amount of free phenols and reducing sugars which were higher in the treated plants. Moreover, application of antioxidants reduced the rot incidence.