The study drug, Aprepitant, is currently used to control chemotherapy induced nausea and vomiting and is also approved for post-operative nausea and vomiting. The investigators' evaluation of it in morbidly obese patients will demonstrate its ability to control nausea and vomiting post-operatively in this subset of patients.

The purpose of this study is to evaluate the effectiveness of Aprepitant, also known as Emend, in reducing post-operative nausea and vomiting in morbidly obese patients. Post-operative nausea and vomiting that occurs in morbidly obese patients can greatly increase the chances of complications during the post-operative period. By treating morbidly obese patients with Aprepitant, the goal is to reduce the risk of such complications that may be induced by nausea and vomiting.

Inclusion Criteria:

Subjects included in this study must be:

• Female
• At least 18 years of age
• Non-smoking
• At high risk for PONV
• Obese with a BMI of at least 45 kg/m2
• Undergoing upper gastrointestinal surgery requiring postoperative opioid analgesia

Exclusion Criteria:

Subjects will be excluded if:

• They have a known allergy to Aprepitant or Ondansetron
• They are currently taking Orap (pimozide), Seldane (terfenadine), Hismanal (astemizole), or Propulsid (cisapride)
• They are pregnant
• They are breastfeeding
• They plan on getting pregnant in the 2 months following surgery
• They are not able to receive patient controlled analgesia (PCA) following surgery
• They have a known drug or alcohol abuse problem
• They have chronic nausea and vomiting