In general, apples are harmless to dogs. However, there are a couple of things to be cautious about: the seeds and too many apples. The Seeds Apple seeds contain amygdlin, a form of cyanide, which is very poisonous to every living thing. Cyanide prevents the blood from carrying oxygen throughout the body. If the dog swallows a few seeds, the body will detoxify itself. Actually, the dog must ingest large quantities of apple seeds to do major damage. read more