In a 42-year-old man with bilateral severe Mooren's ulcers, results of immunologic studies were normal, with the exception of an in vitro blastogenic response of the patient's lymphocytes to corneal stroma. The histologic studies revealed vast numbers of vacuolated neutrophils with intracytoplasmic phagosomes in and about the ulcerating cornea. Although the progression of ulceration was initially unaltered by surgical and pharmacologic trials, systemic immunosuppression with methotrexate may have prevented ulceration of the lamellar tectonic graft.