The ASPCA explains that a dog who frequently eats non-food items such as wood, dirt and rocks is suffering from a condition called pica. In some cases, pica is exacerbated by a lack of exercise, boredom and even anxiety, especially in younger dogs. However, pica is often the result of a medical problem such as a dietary deficiency.
According to the ASPCA, rocks are the most common non-food item ingested by dogs suffering from pica, but dogs also sometimes swallow other inedible items such as plastic containers, clothes and wooden objects, including mulch. Puppies that have pica are typically going through a normal learning phase as they investigate which items are food and which are not. However, if an adult dog has pica, have it checked for a dietary deficiency, digestive disorder, internal parasites or poisoning.
While pica is sometimes a symptom of a more severe medical problem, pica itself sometimes wreaks havoc on a healthy dog. The Daily Puppy warns that it is possible for ingested inedible items, such as wood mulch, to lead to an intestinal blockage or a perforated bowel. These are two dangerous conditions with potentially fatal complications without prompt veterinary attention. Therefore, it is important to determine the cause of a dog's pica to stop the behavior quickly.