Systems and methods for effecting bariatric procedures are disclosed. Each system includes an instrument, a control valve and, optionally, a suction controller. The instrument is in the form of an elongated, flexible member having a distal end portion arranged for anchoring the instrument in the patient's stomach and for enabling fluids to be removed from the patient's stomach. Suction is applied to the patient's stomach by the distal end portion of the instrument to drain gastric fluids and to bring adjacent portions of the patient's stomach into engagement with the instrument to provide a visually perceptible delineation line along which a portion of the stomach may be resected, sealed and tested.
