In recent years it has become possible to detect organic pharmaceuticals and drugs in a few milligrams of a person's hair, using modern analytical methods (RIA, GC MS, GC), whether this person has taken narcotics and other drugs in past times. With the aid of hair analysis it is possible to examine the drug career of a drug addict for up to 1 year, and sometimes for a longer time. This is mostly of great importance in criminalistics and forensic medicine, in the criminal retrospective examination of addicts. © 1990.