12 Weeks Treatment With DDP225 or Placebo in Patients With Chronic Functional Vomiting

Inclusion Criteria: 1. Male or female patients from 18 to 65 years of age, inclusive. 2. History of functional vomiting for at least 12 weeks (which need not be consecutive) in the preceding 12 months, or history of cyclic vomiting with at least 3 episodes in the previous 12 months. 3. Female patients must have negative serum and urine pregnancy tests and be post-partum for at least one year or not breast feeding at the initial screening visit and throughout the study. For female patients able to bear children, an acceptable method of birth control must be used throughout the study. Patients unable to bear children must have documentation of such in the case report form (i.e., tubal ligation, hysterectomy, or post-menopausal \[defined as a minimum of one year since the last menstrual period\]). 4. Able to provide voluntary, written informed consent with full comprehension of all aspects of the protocol. Exclusion Criteria: 1. Serious underlying diseases (cardiovascular, genitourinary, urinary, thyroid or hematological diseases, psychiatric disorders, central nervous system disorders, or coagulation disorders). 2. Clinically significant abnormal examination findings or laboratory tests. 3. Inability to stop taking certain medications, or a planned change in medication (including herbal remedies) which would interfere with study assessments. 4. Use of drugs or ethanol which may interfere with compliance of study procedures or influence study outcome. 5. Presence of a medical condition which could interfere with the interpretation of study data. 6. Significant use of nicotine or caffeine.