Dogs can eat blueberries safely. Blueberries are a healthy, low-calorie treat that contains vitamins C and K, fiber, and antioxidants, which support a dog's immune system, digestion, and overall health. Dogs can have fresh or unsweetened frozen blueberries in moderation. It is important to avoid canned, sugared, or blueberry products with added preservatives or sweeteners that may be harmful. Blueberries can be given as a treat, training reward, or mixed into regular dog food, but they should make up no more than 10% of a dog’s daily diet. Watch out for choking hazards especially with smaller dogs, and always wash the blueberries before feeding. Excessive consumption could lead to digestive upset like diarrhea.