Ground-glass nodules in the posterior basal segment of the lower lobe of the left lung may be associated with diseases such as pneumonia and lung cancer, and are treated mainly by drugs and surgery. Chest CT for pneumonia may show a cloudy elevated shadow with low density, similar to ground glass. Common treatment drugs include antibiotics such as penicillin, glucocorticosteroids such as dexamethasone, and antipyretics such as ibuprofen and acetaminophen. They are mainly used to fight infection, relieve symptoms, and reduce fever and pain. Pneumonia can be cured in most patients after medication and symptomatic supportive treatment, and surgery is usually not necessary. Early chest CT of non-small cell lung cancer may show ground glass nodules or mixed density nodular shadows. Common therapeutic drugs include anti-angiogenic drugs and tyrosine kinase inhibitors. They are mainly used to inhibit the growth and reproduction of tumor cells. Surgical resection is mainly used in the early stage of the disease, and can also be used to destroy the cancer cells by freezing and heating the probe tip. Ground glass nodule in the posterior basal segment of the lower lobe of the left lung may also be lung cancer. It is recommended to seek medical treatment in time and under the guidance of the doctor, and not to take medication without authorization, so as to avoid delaying the condition. Pay attention to rest on weekdays, quit smoking and drinking, and keep regular work and rest.