One and a half year old baby cough how long can be good can not be generalized, for the cold caused by the general 1 week or so can gradually improve, and mycoplasma infection tends to cough will last about 3 weeks, and pertussis baby, such as untreated, and can even cough for 12 weeks long. Different causes of baby cough, how long can be good is also different, can cause baby cough common causes of colds, acute upper respiratory tract infection, mycoplasma pneumonia, whooping cough infection, etc., generally speaking, colds caused by coughing for about 1 week can be improved, acute upper respiratory tract infection in the treatment is often 1 week or so can also be improved. And mycoplasma infection caused by pneumonia caused by cough tends to last longer, usually takes about 3 weeks, and whooping cough infection, such as without formal treatment, the baby can cough for up to 12 weeks long. The exact duration of coughing may be related to the baby’s specific condition, such as the combination of complications may need to be treated for a longer period of time. When the baby cough symptoms, should be timely to the regular hospital, and under the guidance of the doctor for treatment.