How Long do Drugs Stay in Your System?

The length of time a drug stays in your system depends on your height, weight, age, amount of body fat, and your current health. It will also depend on how often you use the drug, and what drug it is. In general, for instance, amphetamines will stay in your system for 1-2 days, barbituates 2-3 days, and methamphetamines 2-4 days.