Solid nodule about 4mmx3mm in the posterior segment of the upper lobe of the right lung can usually be treated with medication, usually due to inflammatory stimulation, tuberculosis, lung tumor and so on. 1. Inflammatory stimulation: solid nodules about 4mmx3mm in the posterior segment of the upper lobe of the right lung may be due to lung inflammation stimulation, resulting in the emergence of lung granulomas to form nodules, the patient can take roxithromycin, ciprofloxacin and other drugs under the guidance of the doctor to treat inflammation, and allergy is prohibited. 2. Tuberculosis: Tuberculosis is a lung disease caused by Mycobacterium tuberculosis infection, the patient will appear in the posterior segment of the upper lobe of the right lung to see solid nodules, you can take isoniazid, pyrazinamide and other drugs under the guidance of the doctor, allergy is prohibited. 3. Lung tumor: Lung tumor is divided into benign and malignant, generally less than 6mm solid nodule is more likely to be benign, and can be regularly reviewed, such as nodule grows faster, and there are burr sign, fuzzy edges and other imaging changes, it is recommended to carry out a puncture biopsy, in order to clarify the nature of the lesion, and if necessary, perform surgical treatment. Right lung upper lobe of the posterior section of the solid nodule about 4mmx3mm may also be caused by air pollution, it is recommended that patients go to the hospital in time for examination, under the guidance of the doctor symptomatic treatment.