Lactate dehydrogenase (LDH) is an intracellular enzyme being released from disrupted cell membrane of human cells and, frequently used as an end-point for cytotoxicity assay. LDH is considered as a stable enzyme that catalyzes the final step of anaerobic glycolysis by converting pyruvate to lactate, coupled with the oxidation of NADH to NAD+ as a response over oxidative stress or cellular damage in the body. This test uses a biomarker that detects the LDH released from the necrotic, apoptotic or injured cell. LDH levels is increased in blood circulation which commonly indicate tissue injuries due to cell death (apoptosis/necrosis), heart attack (myocardial infarction), liver disease, kidney disease, tumor development and several other that involve tissue damage. Thus, the level of LDH can be used as a biomarker for several diseases that involved tissue damage and cell lysis. LDH expression levels can serve as a biomarker for evaluating the impact of probiotics, providing insights into metabolic changes resulting from their administration. The release of LDH from cells is widely recognized as a reliable biomarker for cell death and is increasingly replacing the traditional Chromium-51 release assay in evaluating cell-mediated cytotoxicity.