Bee Mast Cell Degranulating Peptide (MCDP) is a biologically active peptide derived from honeybee (Apis mellifera) venom that plays a role in modulating immune and inflammatory responses. MCDP is a small peptide component of bee venom that can induce degranulation of mast cells, leading to the release of histamine and other inflammatory mediators involved in allergic and inflammatory reactions. Through these effects, bee MCDP contributes to the physiological responses associated with bee stings, including local inflammation, pain, and immune activation. In addition to its effects on mast cells, MCDP has been reported to interact with ion channels and influence neuronal signaling pathways. In cell culture, purified or synthetic bee MCDP is commonly used to stimulate mast cell degranulation, investigate mechanisms of allergic inflammation, and study mast cell activation and mediator release in vitro. Bee MCDP is also used in immunological and pharmacological research to better understand mast cell biology, allergic responses, and the cellular effects of venom-derived bioactive peptides.