In Vernonia v. Acton (1995), the Supreme Court upheld a school district's right to test student athletes, saying that athletes have a lower expectation of privacy and their safety could be compromised by drug use. In Pottawatomie County v. Earls (2002), a court ruled that schools can test students who participate in any extracurricular activity.
Only students in competitive extracurricular activities can be "randomly" tested. Any student that is under "reasonable suspicion" can be "cause" tested. This means a student was observed having abnormal behavior, exhibiting intoxication symptoms or possessing drugs. Urine, hair or oral fluid is tested to detect drugs such as marijuana, cocaine and steroids.
According to the National Institute on Drug Abuse, a 2007 study (Goldberg et al, J. Adolesc Health, 41: 421-29, 2007) found that student athletes who were randomly drug tested had overall rates of drug use similar to students who weren't tested. Some evidence indicated future drug abuse actually increased among those tested.