Friday night I thought I would try nac 600mg , hour later I had a stomach ache which lasted the whole night , tried 300mg yesterday morning stomach ache got worse and lasted all day and I still have slight stomach pain, how can I take nac without getting stomach pains?? I want to try it again because Friday night I didn't wake up to pee which is very rare for me also I woke up feeling pretty refreshed which is very rare too and my sinuses seem quite clear over night and Saturday so I'm sure the nac helped just need to find out how to take it without getting stomach pain.