From what I remember, coffee enemas cause the liver to dump bile (so if you're into cleansing, it's good to eat something high fiber afterwards, to ensure the bile gets permanently removed). I haven't tried NAC, but I've used Vitamin C and it's still my favorite enema additive. I used to use probiotics until I became intolerant of them later. Now I don't use enemas anymore since it's too hard to stand up from and get down on the floor, also my occasional dizziness might lead me to pay too little attention to contamination of the tube or trip over the line. I wish I had a bigger bathroom with more handles to make it easier to get up, down from the floor. I've stopped hundreds of migraines with enemas when I was younger, before I had drugs to prevent them.