Signs of an obstruction in the throat are retching, trying to vomit, and drooling. Thick and foul smelling discharge as well as nasal discharge suggests rhinitis or sinusitis.
The best thing to do is simply any coughing that does not go away over two days, or in cases where it reoccurs often, then do not hesitate to take him to the vet. Coughing in the night could be a sign of some something not right with him. (See Video)

Various reasons
Possible reasons why your dog is coughing could be:
Kennel cough
This is a contagious infection of the respiratory system. The trachea and bronchi become very inflamed. He may develop a dry cough and retch. This condition can develop into pneumonia and is a serious condition so he really needs to see a vet. Many boarding kennels and training classes insist that your dog is pre-vaccinated against kennel cough due to the highly contagious nature of the infection.
Coccoidiosis
Insanitary kenneling can be a cause of this condition. A microorganism attacks the dog’s respiratory tract and lungs.
Distemper
Puppies that are unvaccinated are most at risk from this condition. Adult dogs are less at risk and if they develop distemper, it is usually not too serious as their vaccination gives them a level of protection but it can be fatal to older dogs, puppies and dogs that have a problem with their immune system. Discharge from the eyes and nose as well as coughing and fever.
Allergies
Various allergies can be a cause of your dogs coughing. This could have been brought about by insect bite pollen or inhaled toxins. This can cause a reaction in the mucus membranes giving the dog a cough.
Internal parasites
Wandering roundworms on route up the intestine to the respiratory tract can cause the coughing in your dog. A mosquito can cause heartworm that eventually make their way into the dogs lungs creating coughing. This is a serious possibly fatal condition left unattended.
Fungal infections
Inhaling fungus spores from bird droppings or mold in damp conditions can make the dog cough.
Heart disease
Coughing could be a sign of serious heart problems. An enlarged heart restricting the airway or congestive heart failure could be the cause.
Auto Immune diseases
The dog’s immune system attacks the body tissue creating mucus in the respiratory tract, which in turn makes your dog cough.
Tracheal collapse
Overweight or obese dogs sometimes develop a collapsed trachea and inflammation develops that cause a cough.
Treatment
Your vet may use a blood test or x-rays to diagnose the problem He may prescribe anti-inflammatory or anti-biotic dependent on his diagnosis.
A cough is not something to take lightly. Chances are it is not anything serious or untreatable but for coughing, you really should take your dog to a vet as soon as possible.
This account is just a basic guide and for more information, click here.
