Practical results following from measurements of ethylene oxide residues in polymeric sanitary materials are discussed. The obtained data are affected by the following factors: sample preparation, efficiency of the extraction procedure, the way of injecting the sample, conditions of chromatographic analysis and the interpretation of the obtained results. Further factors depend chiefly on the way of sterilization and on ventilation of the respective materials.The results point unambiguously to a different behaviour of hard polymeric materials in sterilization and to enhanced requirements concerning their ventilation. This must be considered in their repeated sterilization. On the other hand, soft materials cannot be easily ventilated or analyzed.