The clinical picture of an acute abdomen is frequently encountered in emergency medicine. In most cases abdominal pathologies underlie this condition, however, also extra-abdominal diseases may present or cause an acute abdomen. The fact that this condition is potentially life-threatening highlights the importance of instant action. Here, we report on the case of a young woman that presented with an acute abdomen in our clinic. Imaging revealed a massively distended stomach reaching the lesser pelvis. Initially, the etiology for the gastric dilatation remained unsolved. On the same day we performed an explorative laparotomy in which massive amounts of clotted, undigested food was recovered via a gastrotomy. Postoperatively, upon psychiatric consultation, an eating disorder with daily eating binges could be revealed as being the cause for the acute and dramatic gastric dilatation. The patient fully recovered from surgery and psychiatric co-treatment was initiated. This unique case report demonstrates how a psychiatric condition may lead to an acute abdomen, however, it also emphasizes the importance of prompt diagnosis and adequate therapy to avoid complications and allowing for full recovery.