A 26-year-old woman, gravida 3, para 2, came to the emergency room complaining of pleuritic chest pain and shortness of breath. Twelve days prior, she had a vaginal delivery induced by pitocin. Her recovery was uneventful until the morning of admission when she awoke with bilateral pleuritic chest pain radiating to her shoulders, accompanied by dyspnea at rest. She also described mid-epigastric pain with nausea and anorexia. She denied fever, chills, rhinorrhea, cough, sputum production, haemoptysis, vomiting, change in bowel habits, constipation, diarrhea, or leg pain. The patient did not smoke, did not use oral contraceptives, and was on no medications. She had never had abdominal or gynaecologic surgery.She appeared comfortable with normal respirations. The heart rate was 80 beats min-1, the respiratory rate 16min-1, the blood pressure 120/90mm-1 of mercury, and the temperature 37-1°C. The chest was clear. Cardiac auscultation revealed regular rhythm with no murmur, gallop, click or rub. Jugular venous pressure was normal. The abdomen was flat and nondistended with normal bowel sounds. There was mild upper abdominal tenderness with no guarding or rebound. No organomegaly was detected.Arterial blood gas determination showed a pH of 7-42, P02 of 93 mm of mercury, pCO2 of 37mm of mercury, with a carbon dioxide content of 25mmolli-1. A chest radiograph showed no infiltrates or effusions, but demonstrated a large amount of subdiaphragmatic, extraluminal air (Fig. 1).Further history revealed that on the night before her illness began, the patient had engaged in sexual intercourse for the first time in 4 months, including oral-vaginal insufflation.In view of the possiblity of a ruptured viscus, a surgical consultation was obtained. Subsequent laboratory tests included haemoglobin 139 grams litre-1 leukocyte count of 7-1 x 109 litre-1 with 0-64 segmented neutrophils and no bands.Electrolytes, trasaminases, and amylase were normal. KUB showed a non-specific bowel gas pattern and confirmed the presence of free subdiaphragmatic air.The patient was admitted to the hospital for observation. Chest X-rays over the next 48h showed diminution of the amount of free air. Her pleuritic chest pain improved, and she was discharged.