Hi Mucolite syrup is given to make the sputum thin and less viscous, so it becomes easier to cough out the sputum. Asthalin is given to dilate the airways in bronchitis and asthma. asthma is one of the important cause for chronic cough. it is important to do total control for Asthma. repeated Asthma attacks can damage the lungs.In young children, Asthma may not present as a wheezing. You must discuss with your Doctor, and if Asthma is the likely diagnosis, your child should be treated and get prevention inhaler also. You must also know the allergen,which aggravates Asthma, so you can avoid those aggravating causes. We always have to weigh the benefit and side effects of the medicine. If it is Asthma or Chronic bronchitis, he has to take the Asthalin to relieve, and your Doctor will advise him some prevention inhaler, so your child doesn t have to take Asthalin for longer duration. Asthalin is available in Inhaler form, which has lesser systemic side effects as compared to Syrup form. Take care.