Recently, the use of mycophenolate mofetil (MMF) has expanded in dermatological practice. Three patients with PG received MMF in conjunction with prednisone and a fourth patient received MMF monotherapy daily. MMF in combination with prednisone in three of our patients and alone in our fourth patient induced healing of their ulcers. The first patient tolerated MMF apart from gastrointestinal upset, while treatment in our second patient was complicated by staphylococcal and pseudomonal sepsis. The third patient complained of palpitations and headaches.