The number of ulcer biopsies taken depends on the size and location of the ulcer, ranging from 1 to 6 pieces in the case of a single case, and depending on the number of sites of the disease in the case of multiple cases. Ulcer biopsy generally refers to the location of the ulcer lesion, take several pieces of tissue, and then stained, under the microscope for pathological and immunological tests, the most important thing before the biopsy is to take the tissue. If the ulcer is single, generally small ulcers, take 1 to 2 pieces of tissue can be, if the ulcer is larger, is the need for 2 to 4 pieces of tissue for testing, if the ulcer is suspected of malignant changes, it is necessary to take 5 to 6 pieces of tissue in multiple sites, in which case the accuracy is higher. In the case of multiple ulcers, it is necessary to select more than one ulcer surface for sampling, which may require 5 to 6 pieces or even more. Tissue sampling should always be done under the supervision of a medical professional.