Baking soda is safe to eat and found in many common baked foods. According to HowStuffWorks, baking soda is also safe for ingestion through means other than baked goods.
Primarily a leavening agent, baking soda is also effective in beauty and health applications. As explained on HowStuffWorks, baking soda is a remedy for an upset stomach when it is mixed with warm water. It is also in some toothpastes and used by itself for the whitening and cleaning of teeth. Baking soda is useful for skin care and treating sunburns. It is also used as a deodorant and in soothing baths. In all these applications, a small amount of baking soda is ingested, though not as directly as when it is eaten in baked goods.