Plain bread — Food safety facts
Safe to share · Dogs · full breakdown on the linked food page
A plain piece of bread is not toxic, but it is empty calories. Never give raw bread dough — it rises in the stomach and ferments into alcohol.
Short answer
A piece of plain, fully baked bread is not toxic to dogs and is safe as a very occasional treat. Watch for raisins, xylitol, chocolate or garlic in flavoured breads, which are dangerous. Never give raw dough. Bread offers no nutrition, so keep it to a rare, small bite.