A small minority of post-operative gastric bypass patients develop persistent vomiting that is not associated with a physical abnormality and is unresponsive to medical/surgical treatment. In addition to possible nutritional deficiency, patients with persistent vomiting are distressed by unpleasant physical sensations, embarrassment, preoccupation with eating, and worry about health. A vicious cycle of overeating and eating avoidance aggravates tendencies to vomit. A series of cases is presented that illustrates how initial incidents of vomiting, triggered by physical recovery from surgery, are sustained and promoted by behavioral factors, including: (a) self-induced vomiting to control fears of weight regain - akin to bulimia nervosa, (b) classically conditioned vomiting following initial incidents of mechanically induced vomiting - akin to conditioned food aversion, (c) vomiting as a learned escape response to cope with irrational fears of food being stuck, frightening chest sensations and so forth - akin to a food phobia, (d) overeating or eating too fast associated with noncompliance to dietary recommendations. Behavioral treatments for these conditions are presented including procedures of: exposure and desensitization to anxiety provoking meals, shaping procedures or gradually re-introducing foods to build eating tolerance, stimulus control procedures or scheduling eating at regular intervals, and cognitive restructuring to deal with irrational ideas about eating, health, and weight loss.