In 1956 we evaluated a patient who had a debilitating disease of a 2 yr duration, characterized by recurrent vomiting, diarrhea, cachexia, massive edema, hypoproteinemia, and dilated intestinal lymphatics. During our initial evaluation of this patient, we observed that 42% of her circulating protein pool was lost into her gastrointestinal tract daily, whereas normal gastrointesinal loss of protein does not exceed 1.6%. Her disease appeared to represent a classic example of intestinal lymphangiectasia. She was treated symptomatically for 13 yr with essentially no change. In 1969 the patient developed a stage IV diffuse, undifferentiated (non-Burkitt's) malignant lymphoma. Using immunoperoxidase staining, the neoplastic cells were found to contain cytoplasmic IgMKappa, suggesting that the lymphoma had a monoclonal B-cell origin. She was successfully treated with cyclophosphamide, vincristine, and prednisone. Shortly after the initiation of this systemic combination chemotherapy, her serum protein concentration returned to normal, her edema resolved, and she was cured of gastrointestinal symptoms. Moreover, repeat studies revealed that her protein loss had fallen to only 2%. The simultaneous cure of both the intestinal lymphangiectasia and lymphoma with combination chemotherapy suggests new relationships between these conditions as well as new possibilities for the treatment of acquired forms of intestinal lymphangiectasis associated with overwhelming gastrointestinal protein loss.