Acorns are bad for dogs because they contain tannins, which are toxic compounds that can cause stomach upset, vomiting, diarrhea, and in severe cases, liver or kidney damage. They can also pose a choking hazard or cause intestinal blockages due to their hard shells. If a dog eats acorns, it is considered a medical emergency and the dog should be taken to the vet immediately. Symptoms of acorn poisoning include vomiting, loss of appetite, lethargy, abdominal pain, and dehydration. Preventing dogs from eating acorns is important, especially in the fall when acorns are plentiful on the ground.
