Acute accumulation of chyle in the peritoneal cavity is a rare event (less than 100 cases are described in the literature) and is to be distinguished from chylous ascites, which is characteristically chronic. It is frequently idiopathic, and diagnosis is usually made at laparotomy, whenever signs of acute peritonitis impose it. Peritoneal toilette and drainage are the only treatment required, and the prognosis is excellent. We describe the case of a 69-year-old man who underwent emergency surgery for acute peritonitis. Approximately 0.5 liters of chyle were found free in the peritoneal cavity at laparoscopic exploration, without any important underlying pathological condition apart from a blood vessel congestion in the bowel resembling angiomatosis. Laparotomic conversion, peritoneal toilette and drainage, with postoperative low-fat diet, were the pursued treatments. Two years after discharge, chemistry and clinics are normal, without evidence of associated disease or recurrence.