A 25-year-old woman with a history of atopic dermatitis was admitted to hospital with shortness of breath, high fever, cough, and bloody sputum. Chest X-ray showed a diffuse infiltrative shadow. We diagnosed pneumonia, and antibacterial therapy was started ; however, the treatment was ineffective. Echocardiography showed tricuspid endocarditis, and she was thus transferred to our hospital. We selected medical treatment because the case was complicated with severe lung abscesses and pulmonary failure. As a result of appropriate antibacterial medication for 4 weeks, her symptoms and lung abscesses were improved ; however, tricuspid regurgitation and right heart failure continued to worsen. Therefore, the patient underwent vegetectomy and tricuspid valve plasty. No perioperative pulmonary complication was observed. She continued to receive the same antibacterial treatment after 2 weeks. In preceding antibacterial treatment before surgical treatment, it is effective for tricuspid endocarditis complicated with severe lung abscess.