We report a case of co-infection with Nocardia farcinica, Pneumocystis jirovecii, and Aspergillus fumigatus due to tooth extraction in a mildly immunosuppressed patient. This patient did not respond well to a meropenem-based regimen, and the number of lesions was significantly reduced after switching to imipenem. The patient's trough concentration was insufficient when using conventional doses of voriconazole for the treatment of pulmonary aspergillosis. After adding omeprazole, the concentration reached standard levels and symptoms improved. The patient eventually made a full recovery.