A treatment algorithm and preprinted order form developed to reduce the cost of treating antineoplastic drug-induced nausea and vomiting are described. A team including pharmacists, oncologists, and oncology nurses developed a treatment algorithm to reduce the cost of antiemetic therapy for patients receiving antineoplastic therapy at a 719-bed academic medical center. The algorithm incorporated the following concepts: matching antiemetic therapy with the emetogenic potential of the antineoplastic regimen, reducing ondansetron dosages, increasing the ratio of oral to intravenous therapy, and treating delayed-onset nausea and vomiting without using serotonin-receptor antagonists. To help physicians learn and use the treatment algorithm, it was incorporated into an order form for both antineoplastic and antiemetic drugs. Separate order forms were created for pediatric and adult patients. A comparison of outcome data before and after implementation of the practice guidelines showed that the patient outcomes were at least as good after implementation as before. More than a year after the guidelines were implemented, more than 85% of antiemetic regimens prescribed for antineoplastic drug-induced nausea and vomiting were in compliance with the guidelines. A cost avoidance of nearly $205,000 was realized in the first year. Collaboration with oncologists at the start of the care plan was a key element in its success. An antiemetic treatment algorithm, integrated with a preprinted physician order form, was well accepted and has reduced expenses for antiemetic therapy.