I have had the flu a number of times and it never made me vomit. Influenza is an upper respiratory disease. Are you talking about an intestinal virus or influenza?
Not to be flippant, but most of us don't really have the flu when we think we do. Most of it is just upper respiratory thingeys. The flu normally kicks the life out of you. I had it one year and collapsed when I tried to walk across the room.
I also have severe airborne allergies so I don't play around with this stuff.