Metabolites are the byproducts of THC (or any other drug) after it has be threw your system and broken down. You have to wake up first thing in the morning and drink about 8 glasses of water or more for a better chance of passing. If you start before that, you're causing yourself unneccesary discomfort. Piss a few times, because this is full of metabolites. Also, only give a mid-stream sample. Here's something that I learned from ImN2pot, so I'll give him his props for this: You need to start taking creatine a few days before the test. You can get them from the health store. You should get the powder form. This is why one has to take this: When you drink alot of water, it lowers your creatine to a very low level, and this is how they know that you've been drinking alot of water to hide something. When you take creatine, it gets it back to it's appropriate level and the lab thinks that you are clean.