PETfraction is a veterinary version of Maitake D-Fraction Pro developed in response to requests from holistic veterinarians and pet-loving consumers. It contains purified and standardized "active proteoglucan" from Maitake mushroom (Grifola frondosa) at professional strength. The active proteoglucan, often referred to as "D-Fraction" by scientists, is a unique beta-glucan conjugated with protein, that has been identified and isolated as a substance responsible for the potent immune-activating property of Maitake mushrooms. Maitake D-Fraction Pro has been the subject of many clinical and non-clinical studies in the US, Japan and other countries.