you can give a dog milk of Magnesia (2 to 5 Ml per pound orally every 4 to 6 hours) or Mineral oil (10 to 50 ml per pound add to food)
I hope this helps, you can find this info in the Dog Owner's Home Veterinary Handbook and you can get it at
Discount Pet Supplies, Pet Supply, Online Pet Supplies It is a great book, I use it all the time and everyone I know calls me asking me questions about their dogs, and I get all my info from this. Best book ever.