- having used corticosteroids, oral retinoids, or other immunomodulatory agents within one month of participation in the study; non-steroidal anti-inflammatory agents (e.g., aspirin, ibuprofen, etc.), acetaminophen, or oral antihistamines chronically within one month of participation in the study or any use within five days of participation in the study; topical medication (including steroids, retinoids, and anti-microbial drugs) within two weeks of participation in the study, systemic antibiotics within two weeks of participation in the study; any preparation or medication (OTC or prescription) applied to the ulcer within 48 hours of participation in the study