To the Editor.— The article "Hyperbaric Oxygen Therapy for Pyoderma Gangrenosum" by Thomas et al in theArchives(110:445-446, 1974) prompts me to report on a patient who has just completed therapy. Report of a Case.— A 22-year-old man first developed nodular ulcerative lesions in November 1973 on the anterior surface of his left leg. He has been treated for ulcerative colitis in the past and has been under treatment for this condition with corticosteroids and antibiotic therapy. On Feb 23, 1974, he had an exacerbation of a different type of lesion, which was also present at the anterior surface of his left leg. The patient developed a bluish-black, boggy, undermining ulcer for which a diagnosis of pyoderma gangrenosum was made and he began receiving treatment with antibiotics, wet compresses, increased corticosteroid dosage, and multiple vitamins. He continued to develop new lesions in spite of his intensive corticosteroid