A cough lasting for 15 days in a 6-month-old baby should be evaluated carefully, as young infants can become unwell more quickly than older children. The cough may be due to a common viral cold, mild throat infection, nasal congestion, allergy, or sometimes a chest infection. Keep your baby well hydrated with regular breastfeeding or formula feeds, as fluids help keep mucus thin and prevent dehydration. You can use saline nasal drops and gentle suction if the nose is blocked, especially before feeding and sleep. Keep the baby away from dust, smoke, strong perfumes, and cold air, as these can worsen coughing. Avoid giving over-the-counter cough syrups or antibiotics without a doctor?s advice, because many cough medicines are not safe or useful for very young babies. Since the cough has already continued for more than 2 weeks, it is advisable to consult a pediatrician for a proper check-up, especially if the baby has fever, fast breathing, wheezing, poor feeding, vomiting, disturbed sleep, bluish lips, or unusual tiredness. The doctor may listen to the chest and decide whether any treatment or further tests are needed. Early medical evaluation is important in infants to make sure there is no chest infection or breathing problem.