Greater awareness of the benefit of medical management of neoplasia has resulted in greater client demand for therapy and increased use of chemotherapy by practitioners. Complications of anticancer therapy, therefore, can be expected to an increasing complaint of clients contacting emergency and critical Care facilities. The efficacy of chemotherapy consists of a does dependent cytotoxic effect on rapidly dividing neoplastic cells. As these drugs charcteristically have a narrow therapeutic to toxic ratio, damage to normal host tissues is the major risk with aggressive protocolos. The most common adverse effects are myelosuppression with fever and spesis secondary to neutropenia and gastrointestinal toxicity with vomiting or diarrhea. With awareness of the toxicity of specific anticancer durgs, the practicing emergency clinician can rationally intervene to overcome what is often short term, but life-threatening crisis.