Your dog looks at the outdoors as a wonderland full of things to smell, chase and eat. Unfortunately, some of those things to eat can be dangerous, like poisonous toadstools. Many types of mushrooms are completely harmless to dogs, but you should always take precautions around these potentially lethal snacks nonetheless.
The chief danger with toadstools is that safe varieties can be extremely difficult to differentiate from poisonous varieties, and they can grow right next to each other. Poisonous toadstools can cause a variety of symptoms, ranging from vomiting and diarrhea to neurological effects and organ damage.
For your dog’s safety, you should keep him away from any mushrooms while you're out on walks together. Regularly check your yard, especially during rainy times of the year, for mushrooms. Removing these fungi before your dog has a chance to discover them is the best way to ensure his safety.