My dog just ate a little bit of chocolate cake...will she be ok?

She will likely be fine. She may have a little bit of an upset tummy (diarrhea, etc). It sounds like she didn't consume enough chocolate for it to be toxic for her...But keep a close watch on her to be sure! It's the theobromine in chocolate that is toxic to dogs. The darker the chocolate, the more theobromine. Generally milk chocolates and stuff will just cause gastrointestinal upset...If it's very dark chocolate or baker's chocolate, for example, it could be toxic and very serious!