How does Zofran work?

Zofran (ondansetron) blocks the action of the brain chemical serotonin. Serotonin is involved in your body’s nausea response. Serotonin is a key brain chemical for many body functions, but Zofran blocks only part of its action, which is why it is called a “selective” serotonin antagonist. It is those specific actions of serotonin that can trigger nausea and vomiting.