Any other symptoms? How's her appetite? Activity level? mood? If all else is normal I would just cut back things in her diet that can cause loose stool--milk, apple juice, etc,. and give her some things that will help firm it up like bananas, rice, applesauce. A good juice alternative is white grape juice. Also yogurt is your exception to dairy--it's pro-biotic and helps regulate the digestive system. A yogurt a day will help her tummy and digestive system tremendously. We like the yo baby products since they are organic and don't use high fructose corn syrup. (They have them at publix and are a nice small size for babies an toddlers).
If she has other symptoms, it's probably just a bug which would mean you would also want to change her diet to the above and just keep her hydrated. If she starts acting lethargic or gets a fever, call your Dr immediately.