Coughs

A chest infection is the usual cause of a cough. Occasionally
asthma can start as an irritating cough which may occur at night
or on exertion.Occasionally a cough will herald a more serious illness.
Cough syrups are not worth spending money on. You can get good
relief either from 'Simple linctus' mixed with a little warm water or
from a steam inhalation. 

See your doctor if;

you cough up green sputum for more than 2-3 days. This is 
probably an infection for which we would give antibiotics.

you have a cough which lasts for weeks and does not respond to 
antibiotics. There may be a number of possible reasons for it.

you feel short of breath, cough up blood or lose weight.
These symptoms need to be investigated by the doctor.