If your dog eats things it shouldn't there may be a good reason to be concerned. Dogs will frequently nibble on grass, though some dogs prefer it more than others. Eating grass is generally considered safe as long as it is not heavily coated in chemicals and your dog is otherwise healthy. However, eating a lot of dirt can be dangerous because it can clog your dog's digestive tract. Chewing rocks can cause tooth and gum damage, and choking is a serious hazard. Dogs are generally considered safe to eat their poop; however, eating the poop of other dogs or animals is a cause for concern because parasites, viruses, and toxins can be transmitted through feces. Many dogs enjoy playing with and eating rocks, which can be dangerous to their health. Eating non-edible items such as rocks, dirt, and sticks can be a sign of pica, which is thought to be caused by a deficiency in essential minerals or other nutrients. It is possible that eating dirt helps puppies understand their surroundings better, but eating a lot of it is still a concern.