A 67-year-old man was admitted with dry cough and shortness of breath. He had no smoking history and oral hygiene was good. Chest CT revealed massive bilateral pleural effusion. Meanwhile, abdominal ultrasound and echocardiography showed moderate ascites and pericardial effusion. Pleural fluid T-SPOT.TB result was positive. The patient was considered to have tuberculous polyserositis and started HRZE diagnostic anti-TB treatment. However, the patient then developed weakness, loss of appetite, oliguria, decreased pulse pressure. Considering the signs of pericardial tamponade, an emergency pericardiectomy was performed. Thickened pericardium adhesions were seen during the operation, some of which were obviously calcified and narrowed, and some were cheese-like lesions. Histopathology of the pericardium showed fibrous tissue hyperplasia, collagenization with exudation of inflammatory necrosis, and a positive TB FISH result. A diagnosis of tuberculous constrictive pericarditis was confirmed after surgery. We adjusted the anti-tuberculosis regimen to meropenem, moxifloxacin, isoniazid, rifampin, he complained of worsening chest tightness, and large extensive pleural fluid was seen in chest CT after one month of treatment. Linezolid 600mg once daily along with steroids was then added to the anti-TB regimen. Thirteen days after intake of linezolid, asymptomatic black tongue was observed (Figure 1B), and tongue swab detected Escherichia coli. After completing 2 months of the anti-TB regimen containing linezolid, his tongue discoloration disappeared 10 days after discontinuation of linezolid.