Probiotics are recommended to improve human and animal health; however, in vivo assessment of safety aspects of probiotics is an important concern to consider prior to the administration of probiotics into human. Certain bacteria may produce dermonecrotic toxins and one of the crucial parameters of toxicological profiling of probiotics is the assessment of dermonecrotic properties which may be induced upon administration of such bacteria. In this chapter, we describe the method to assess the dermonecrotic properties upon administration of probiotics.