Sodium polystyrene sulfonate (Kayexalate) and calcium polystyrene sulfonate (CPS, Kalimate) are commonly used to reduce serum potassium. There were some published evidences of severe gastrointestinal complications from the administration of these agents such as colonic necrosis with or without perforation and acute obstruction. The authors reported a 52-year-old male patient being critically ill from severe soft tissue infection of the right leg and sepsis. Hyperkalemia had occurred due to renal insufficiency and required several doses of Kalimate to reduce the serum potassium level. Subsequently, the patient developed complete intestinal obstruction and an exploratory laparotomy was performed. The intra-operative findings were distended stomach and the small bowel contained a large amount of intraluminal affected Kalimate that was removed via gastrotomy and enterotomy. These findings suggested that the inspissated Kalimate could lead to significant obstruction of the gastrointestinal tract in some groups of patient.