Higher Logic - "Niacin has been shown to work on occasion. Byrd Labs tests conclude that niacin doesn't work at all. In other words, something else probably caused a negative, not the niacin." http://my.marijuana.com/7-11b.php3 I posted that i had a drug test, and i was worried that i might fail. i said that i had taken niacin 4 days prior to the random drug test, and i drank about 150 ounces of water a day. i passed my drug test!!! with a zero thc level. it was awesome. they let me off reporting probation because of my passed test. ps, i didnt write this to promote niacin, abstinence(sp?) is the only sure way to beat a test, i wrote it to say it worked for me.