Is it okay to take aspirin tablets with an empty stomach? i use 400mg aspirin + 240mg vitc efervescent tablets.

No, it is not.: If you don't eat before taking an Aspirin, you may get some stomach irritation, followed by a stomach ache, but it shouldn't be too severe. But, I would recommend having at least a small snack before taking one

Depends on your body: If the aspirin is (ec) Enteric Coated it will have little upset to the stomach but will be less of a pain reliever. If it is not EC then empty stomach pain depends on the person as a side effect. Although, continuous use will not protect from the side effect of stomach pain and other complications.