Aprepitant Capsules are used to prevent nausea and vomiting caused by cancer chemotherapy; aprepitant is usually taken once daily, with or without food, during the first few days of your cancer chemotherapy treatment. It is used together with other medications to prevent nausea and vomiting that may be caused by chemotherapy. Aprepitant Capsules is given ahead of time and will not treat nausea or vomiting that you already have. Aprepitant capsules are for use in adults and children who are at least 12 years old.