Pepto Bismol nor any other medicines can cure the stomach flu but the Pepto Bismol can help with the diarrhea that may accompany the stomach flu.
Other than that there's not too much you can do for the stomach flu other than staying hydrated, keeping your electrolytes up, eating bland foods, avoiding dairy products and getting plenty of rest.
You can keep your electrolyte levels up by drinking some pedialyte which is great to drink when you have the flu or stomach flu.