Dog Health Questions - Dog Constipation Causes:
Dog Constipation is usually caused by eating bones or other indigestible matter. There are other, more fundamental causes of dog constipation particularly if associated with alternate bouts of diarrhoea.

Dog Health Information - Treatment of Dog Constipation:
1) The first aid type of treatment of canine constipation is liquid paraffin.
2) Natural Suppliment - Natural moves for pets, see link below:

Support Cat & Dog Digestive System Health, Healthy Bowels & Stools Naturally

hope this helps!