Canadian Brand. Foley's Functional Fungi Digestion & Immune Support Treats are designed to promote optimal gut health in dogs. The Digestion & Immune Support treats contain Turkey Tail and Reishi mushrooms, which are rich in immune-boosting compounds. Packed with prebiotics from Chaga mushroom, these treats support the growth of beneficial gut bacteria. Whether your dog struggles with occasional tummy troubles or digestive issues, these treats can help promote digestive comfort and regularity.