If your dog is constipated, you can try to give him or her a spoonful of olive oil - or even better - paraffin oil, which is a lubricant available through pharmacies, in order to help the passage of stool through the bowels. If your dog is repeatedly struggling with constipation, or if symptoms do not improve, consult a veterinarian. After successful treatment, your dog should continue a high-fiber diet. It is often sufficient to simply add a few, 2-6 teaspoons worth of bran with food.