Wild mushrooms growing in the lawn may be harmful to dogs, so it is unwise to allow dogs to eat mushrooms found outdoors. Most little brown mushrooms in yards are harmless, but pet owners need to remove all mushrooms from their yards for safety's sake.
Signs that a dog may have eaten a toxic wild mushroom are vomiting, diarrhea, drooling and watery eyes. The dog may also manifest symptoms such as slow heartbeat, lethargy, a tender abdomen, depression, jaundice and seizures. A pet displaying these symptoms should see a veterinarian, and the suspected mushrooms should be put in a paper bag for examination by the doctor.