DRY COUGH

hello doctors.
i have a patient having severe cough since 10 years. he is a smoker but has reduced smoking now. his throat is always irritated and he has to cough a lot. there is no particular time of cough. please guide me to treat this patient.
thanks.....

 

http://www.ayurvedaconsultants.com/caseshow.aspx?ivalue=engoogle213