In the United States, more than 149,000 new cases of colorectal cancer are expected in 1994. Surgery remains the most effective method of treatment for this disease. Because these operations often result in formation of an ostomy, ET nurses frequently care for patients with colorectal cancer. Many of these patients will receive additional types of therapy after operation, including such traditional therapies as radiation and chemotherapy. Biotherapy, one of the newest therapeutic modalities in cancer care, is increasingly being used in the treatment of colorectal cancer. Because the ET nurse may be one of the few nurses caring for patients throughout the course of their disease, knowledge of the various biotherapeutic agents and the management of patients receiving them is vital.