Intramuscular progesterone has been reported to be infrequently associated with acute eosinophilic pneumonia in patients who have recently undergone in vitro fertilization. A 27-year-old female at 5 weeks gestation after in vitro fertilization presented with cough, fever, dyspnea, bilateral infiltrates, and eosinophilia. All infectious, neoplastic, and autoimmune evaluations were negative. She gradually improved with supportive care. This case demonstrates that progesterone in sesame seed oil may be an inciting agent for eosinophilic pneumonia and that removal of this agent may be sufficient for recovery in mild cases.