How long it takes for Mycoplasma pneumoniae to turn negative in children depends on the specific condition of the child and cannot be generalized. A positive Mycoplasma pneumoniae in children indicates that the patient is infected with mycoplasma, which is a relatively common pathogenic microbial infection in clinical practice. Common clinical manifestations may include headache, cough, coughing, fever, and loss of appetite. Mycoplasma pneumoniae pneumonia lesions are self-limiting, and if the child has mild symptoms, they can resolve on their own without treatment, and the lesions can turn negative after 2-3 weeks. For severe pneumonia and mycoplasma infections, treatment is required under the guidance of a physician, and common and commonly used antibiotics, such as azithromycin and roxithromycin, are usually used to treat the lesions, which usually turn negative after 3-4 weeks of active treatment. In addition, if the result has turned negative and achieved the effect of cure, you also need to pay attention to keep warm, do not catch cold, do not eat spicy, cold, stimulating food.