ANSWER: D-mannose is generally considered safe for dogs when given in appropriate amounts. It is a naturally-occurring sugar that can help to flush bacteria out of the urinary tract and prevent urinary tract infections (UTIs).
However, it is important to consult with your veterinarian before giving D-mannose to your dog to ensure it is safe and to determine the appropriate dosage.
Your veterinarian can also monitor for any potential side effects and can help to treat any underlying conditions that may be causing UTIs in your dog.