3mm solid lung nodules may be tuberculosis or old foci, or may be caused by malignant tumors, etc. General treatment, drug treatment or surgical treatment should be chosen according to the etiology. 1. Tuberculosis: mainly take anti-tuberculosis mycobacteria as the principle of treatment, take isoniazid, rifampicin, pyrazinamide, streptomycin and so on orally according to the doctor’s prescription, and use the combination of drugs and the whole course of drugs. 2. Stale lesions: If you have previously suffered from pneumonia or tuberculosis, solid nodules may be detected in the lungs after leaving fibrous scarring foci. Patients usually have no special symptoms, and regular review is sufficient. 3. Lung malignant tumor: for example, lung cancer, mainly including squamous lung cancer and adenocarcinoma of lung, if it belongs to early malignant tumor, it can be resected by surgery in time, and then combined with individual situation to carry out radiotherapy and chemotherapy to inhibit the growth of cancer cells, chemotherapy drugs can be chosen to be etoposide, cisplatin, carboplatin, and so on. The 3mm solid lung nodule may also be caused by other reasons, which need to go to the regular hospital as soon as possible, under the guidance of the doctor for targeted treatment, so as not to delay the condition.