Hi. one my friends uses aspirin one a day. he wants to use vitamin e. how many hours should he take it after aspirin to prevent contradiction and internal bleeding?

If it is' low dose' aspirin 81mg in US) it can be taken at the same time without a problem. It will not cause bleeding

Some sources suggest that there is a slight increase in bleeding risk when taking the two medications together, but the recommendation is only to watch for signs of bleeding (feel free to ask in a separate question for more information about what to watch for). However, most people who take both tolerate them well. The bleeding risk is not affected by taking the two at different times of the day.