You can include in medical expenses the costs of buying, training, and maintaining a guide dog or other service animal to assist a visually impaired or hearing-impaired person, or a person with other physical disabilities. In general, this includes any costs, such as food, grooming, and veterinary care, incurred in maintaining the health and vitality of the service animal so that it may perform its duties

This information is found in Publication 502, Medical and Dental Expenses.