Introduction: Septic pulmonary embolism is a rare disease. It occurs when a pathogenâ€Âcontaining thrombus embolizes to the lung. We experienced a patient who had deep vein thrombosis due to physical immobility, and sequentially had septic pulmonary embolisms. Computed tomography showed a thrombus in the pulmonary artery and multiple nodules with surrounding blood vessel conversion. We noticed that the patient had periodontitis, and we used phosphomycin, which was quite effective. In conclusion, computed tomography is useful for diagnosing a septic pulmonary embolism. Antibiotics are key drugs in controlling this disease.