What can i take to get marijuana out your system fast?

You don't. If you've never smoked before, or use it rarely, it will clear out quicker, but any process you do to clean your system will be ineffective. You can drink lots of water to dilute you urine, but not too early because then you just cause your self unecessay suffering. Take creatin and B vitamin supplements. DONT EXCERCISE! If you only have three days, this will NOT work, and will actually higher you chance of a positive result. THC is stored in you fat cells, and during excercise it is released. So only excercise to clean your system if you have about two/three weeks to do it, and always stop about 3 days to a full week before you test.