Glycine is an essential component of important biological molecules, a key substance in many metabolic reactions, the major inhibitory neurotransmitter in the spinal cord and brain stem, and has anti-inflammatory, cytoprotective, and immunomodulatory qualities.Based on available literature we discuss some important biological properties of glycine and give a short account of our own studies in this field.The main area of glycine research has traditionally been associated with its role as a neurotransmitter in the central nervous system. During the last few years there has been a mounting interest in effects on other organs and tissues as well. Glycine-gated chloride channels, originally demonstrated on neurons in the central nervous system, have been found on most leukocytes and a number of other cell types. This has provided a unifying mechanism of action that explains how glycine may influence such important and diverse biological processes as transmission of nerve signals and initiation of the immune response.Glycine is a simple, easily available and inexpensive substance with few and innocuous side effects. Despite the recent unveiling of tantalizing aspects regarding its mechanism of action, biological activities and therapeutic potential, clinical use has remained scant.