There is no guaranteed way to get weed out of your system faster than it naturally does. Some of the methods that people use to try to flush weed out of their system, such as drinking lots of water, taking detox products, or exercising, are either ineffective or risky. The best way to avoid testing positive for weed is to abstain from using it for a sufficient period of time before the test. However, if you are a medical marijuana patient or live in a state where weed is legal, you might have some legal protections or options to challenge a positive test result.