Hair is a unique matrix that provides a calendar of previous use of drugs and medications, and therefore it complements the use of blood and urine which both have a limited window of detection. Segmental analysis may also provide a close insight to the temporal pattern of use.

The Society of Hair Testing recommends hair testing for several toxicological investigations including post mortem toxicology, drug facilitated assaults, child custody cases and driver's license regranting. Besides the common testing for drugs of abuse and medications, testing for alcohol markers such as EtG and FAEE in hair are becoming more important as complements to the blood biomarkers CDT and PEth. This lecture will give an overview of how hair as a matrix can assist the toxicologist in the interpretation of casework from these different areas but also highlight some of the limitations.