Background <p>Eosinophilic gastroenteritis (EGE) is an uncommon condition defined by the presence of gastrointestinal symptoms in conjunction with an abnormal accumulation of eosinophils within the intestinal wall. The disease can manifest with varied symptoms depending on the depth of infiltration into the bowel wall. EGE accompanied by ascites is a rare occurrence mostly associated with the subserosal type. This case highlights a rare presentation of subserosal EGE manifesting with eosinophilic ascites, emphasizing the diagnostic challenges and the importance of considering this entity in patients with unexplained ascites and gastrointestinal symptoms. Further, it emphasizes the recognition and management of subserosal EGE and thereby expands the current understanding of its clinical spectrum.</p> Case Presentation <p>A 20-year-old male presented with diarrhea, vomiting, abdominal pain, and dyspeptic symptoms for a 3-week duration. He had a leucocytosis of 22,990 cells/mm³ with significant eosinophilia (14,570 cells/mm³, 64.3%) and a normal serum IgE level (89&#xa0;IU/mL). A contrast-enhanced CT of the abdomen and pelvis revealed edematous thickening of the bowel wall with moderate ascites. Diagnostic paracentesis confirmed the presence of high eosinophils. Significant eosinophilic infiltration was identified in biopsies taken from the ileum during endoscopy. Parasitic infections, other possible systemic diseases, and bone marrow pathologies were excluded. EGE was suspected, and daily prednisolone 20&#xa0;mg was started. After 7&#xa0;days of treatment, a significant improvement in symptoms was noted, with eosinophil count returning to normal values.</p> Conclusion <p>This case highlights the importance of considering eosinophilic gastroenteritis in patients who present with gastrointestinal symptoms and ascites associated with peripheral blood eosinophilia, as most patients respond well to steroids, resulting in better patient outcomes.</p>