Detoxification A metabolic process whereby a parent substance is changed to a daughter product (metabolite) that has lessened toxicity. Diffusion The spontaneous movement of a substance from a high concentration gradient to a lower concentration gradient. Disposition The term used to describe the kinetics of a substance in the body.  It encompasses absorption, distribution, metabolism, and elimination of a chemical. Distal Away from a point of reference.  As used in medicine, something distal is farther away from the main body.  For example, the foot is distal to the knee. Distribution Movement of a substance from the portal of entry to other areas of the body. DNA Deoxyribonucleic acid. The very large molecules in the nucleus of all living cells.  It carries the genetic code. Dose The amount of a substance received at one time.  Dose is usually expressed as administered or absorbed dose (e.g., milligrams material/kilogram of body weight).