Breakfast cereal — Food safety facts
Feed with care · Dogs · full breakdown on the linked food page
Sugar and often raisins, which are toxic to dogs. Check the box before sharing.
Short answer
Yes, a few pieces of plain cereal are usually okay, but it's not a good regular treat. Cereal is often high in sugar and offers little nutritional benefit for dogs. Just offer it dry, watch for any stomach upset, and call your vet if your dog seems unwell.