A proliferative foci in the lower lobe of the left lung is a type of lung infection and is a benign lesion. If the test results show that the area of the left lower lobe proliferative foci is relatively small and does not affect the normal lung function of the patient, and the patient does not experience any other maladjustment in life, no additional treatment is needed, and the patient only needs to pay attention to avoiding spicy food in diet, but must go to the hospital for follow-up at any time. If the area of the proliferation foci in the lower lobe of the left lung is too large, causing chest tightness and shortness of breath, the patient needs to go to the hospital for further examination because lung infection can lead to many diseases, such as tuberculosis is one of the more serious ones, and tuberculosis is highly contagious, so it is important to actively take anti-tuberculosis medication to avoid unknowingly infecting others.