To the Editor: The existence today of various chemotherapeutic regimens of proved usefulness in the treatment of certain neoplastic diseases, particularly those involving the hematopoietic system, is due in large measure to the extensive chemotherapeutic trials pursued by a number of hematology-oncology Cooperative groups.However, one toxic manifestation of such chemotherapy —namely, gastrointestinal toxicity — appears not to have received sufficient critical attention. The administration of nitrogen mustard, daunomycin, and the nitrosoureas (1,3-bis[2-chloroethyl]-1-nitrosourea [BCNU] and l-[2-chloroethyl]-3-cyclohexyl-1-nitrosourea [CCNU]) is followed in almost every case by vomiting. Within two hours, the patient is seized by violent nausea and vomits uncontrollably and repeatedly . . .