Hello. Thank you for asking at HCM. I understand your concern. It is very important to know the cause of cough since 6 months. Though it is very important to know the details of the cough & other symptoms (if any), I would suggest your daughter a few investigations if not done already: CBC, ESR, Manteux Test, Chest X-Ray, serum IgE, Allergy testing. I would suggest her to take a combination of montelukast & levocetirizine for 2 weeks. She will improve if th ecause will be allergic. There are other medicines for different conditions causing cough also, but they can be advised only after detailed assessment and diagnosis. I would also suggest you to keep her away from smoke, dust, air pollution & cold air; also please avoid cold water, cold drinks & cold foods like ice cream etc. Hope this will be helpful to you. Wish your daughter a quick recovery and best of the health. Regards.