(6 oz. bag). Our Forrest Natural Brand has developed the first dog biscuit with the immune boosting and stimulating Coriolus Versicolor mushroom. The Coriolus Versicolor mushroom has over 400 studies worldwide concerning the claim that it helps to boost and stimulate the body’s own immune system. It is also packed with Vitamins along with Glucosamine, Chondroitin and Carotene for bone and joint health. Boosting and stimulating your pet’s immune system will help to give them the necessary assistance to maintain a healthier life.