Elek Medium is used in microbiology for the detection of toxin production by Corynebacterium diphtheriae. It supports the Elek test, a gel diffusion method where bacterial strains are streaked perpendicular to a strip impregnated with diphtheria antitoxin. If the organism produces toxin, visible precipitin lines form at an angle to the growth streak, indicating a positive result. This helps identify toxigenic strains responsible for diphtheria, aiding in diagnosis and public health control. The medium is essential in clinical labs for confirming the pathogenic potential of C. diphtheriae isolates.