Yes, crab apples are safe to eat. They are not poisonous and can be eaten raw, although they tend to be quite tart, acidic, and sometimes bitter. Many people prefer to eat crab apples cooked or baked, which brings out a tastier flavor. Crab apples are rich in fiber, vitamin C, and antioxidants. It is important to avoid eating the core and seeds because they contain compounds that can convert into toxic cyanide, but the amount in crab apples is very small, so accidental consumption of a few seeds is not a concern. Crab apples are often used to make jellies, jams, pies, and other baked goods due to their high pectin content and tart taste.