Mississippi Criminal and Family Law BlogCurrently, there are no federal laws that make it illegal to cheat on a drug test. Some studies suggest that up to 10% of all drug samples have been altered in some way, which means that the number of drug users who are getting away with their habit is actually quite high. While the federal government is not really doing anything to address this issue, individual states are. States like Texas, South Carolina, and Oregon have made it illegal to cheat on a drug test, and guilty individuals can face significant fines and even jail time. However, Mississippi is not one of these states, and cheating on a drug test is still legal.