Poisoning test is an effective means to test drug addicts, which can find out the degree of drug abuse of drug addicts-anyone who walks by will leave traces. After injecting or taking drugs, besides urine, other substances such as sweat, feces, tears, hair, nails, etc. They all contain used drugs or drug metabolites to some extent, so they can be used as evidence for drug testing. As long as you don't cut your hair, you can completely present the drug abuse process in the past few months, which is considered to be one of the most effective methods at present. Although dyeing hair will make the test results discounted, whether there is drug abuse can still be tested, and any hair can be tested, but hair is the most convenient sample to obtain.