Drugs are detectable in saliva immediately upon use. While drug use is detectable in hair for several months, drugs only remain in saliva for approximately 24 hours. Marijuana and THC remain for about 12 to 24 hours and cocaine remains for up to 24 hours, while opiates, PCP, amphetamines and methamphetamines can be found in saliva for up to three days. Learn more about the saliva drug test using our Hair and Saliva Drug Test Guide and interviews with drug test experts Greg Johnson, Elina Smith and Mike Clark
