What would happen if a dog ate sand?

The dog's intestinal track could become blocked. This happened to my friend's dog. They did several x-rays and determined that it was impacted sand. Each time the dog has pooped it is small amounts of sand that has been loosened. We are still waiting for him to finish passing all the sand that was in his system. He was very sick for awhile, we didn't think he'd make it through the night at one point. The vet thought he'd have to have surgery. He became slightly dehydrated and needed fluids and is on antibiotics to keep him from getting an infection. Dogs shouldn't eat sand..it is bad for them and can clump block them up quickly!