Soothe and upset stomach with Rhubarb tea with 1/2 teaspoon baking soda added to it.

To whiten stained teeth: 1 cup of strong chamomile tea, juice of 1 lemon, 1/4 cup vinegar and 1 tablespoon baking soda. Add lemon and vinegar to tea. Mix a few drops of this with 1 tablespoon of soda and brush teeth several times a day. It will help remove stain such as coffee and cigarettes.