How does baking soda clear a slow drain?

I came across this tip in one of those ads trying to sell a book or magazine. “Learn how to clean your drains with baking soda on page 324!”. I had a box of baking soda that was in the fridge and a slow drain, so I thought why not. It’s got to be a lot less toxic than drano. I poured some down after it had finished draining for three days in a row and magic. The drain works great. I’m trying to figure out why that worked. It’s not caustic or acidic, so how does it work? It’s Friday and this is social, so go wherever you want with this.