Dogs sometimes eat grass if they feel nauseous however if they eat too much it can cause a blockage of the intestines. Symptoms of this would be sudden lack of appetite, vomiting , diarrhea or change in stool, and lethargy. If you see any of these signs I would bring her in for an exam.
For upset stomach you can give pepto bismol and I will direct you to a site with information and dosing. http://www.petplace.com/drug-library/bismuth-subsalicylate-pepto-bismol-kaopectate/page1.aspx
You may want to give her a bland diet of boiled chicken ( no bones, no grease) and cooked white rice for the next day or two as this is soothing to inflamed intestines.