What's best medication for a tummy flu? How good is Oseltemuvon capsule?

Unfortunately there is nothing that can really be done for a flu. It is a virus that must run it's course and go away on its own. You need to be sure that you drink PLENTY of liquids to stay hydrated though. Water is okay if that is the only thing you can hold down. But sips of sof drinks like 7-Up help to calm the tummy.

I don't know anything about the capsule you are speaking about.