The article presents the effect of the effective microorganisms and silver compounds addition on the flash point of new and used oil. The work describes environmentally friendly additives to engine oil. Next the ignition point of the engine oil were described. In the further part, the research stand and methodology were presented. In the main part of the article the flash point values for new and used oil compared to oils with the effective microorganisms and silver compounds addition were shown. New and used oil samples were mixed with effective microorganisms in the form of a liquid (2.5 ml and 5 ml) and ceramic tubes (3 pcs. and 6 pcs.). In addition, silver solution and silver compounds were mixed in the same amounts as the liquid effective microorganisms. In summary it was stated, that adding of the effective microorganisms to the fresh oil in liquid form causes the flash point to drop significantly. It follows that effective microorganisms in liquid form have a very negative effect on the properties of the oil. In the case of microorganisms in the form of ceramic tubes, which in this larger amount slightly increase this point compared to oil without additives. Regardless of the type of silver and its quantity, very low flash point values were obtained. For used oil the best results are obtained with the addition of microorganisms in liquid form. For the used oil the addition of silver compounds does not have the beneficial effect of restoring the original properties.