Lysozyme is an enzyme with well-documented antibacterial properties, found naturally in various secretions including human milk. Its primary mechanism involves hydrolyzing the peptidoglycan layer of bacterial cell walls, especially in Gram-positive bacteria. This enzymatic activity underpins its consideration as a supportive agent in the management of mastitis, an inflammatory condition of the mammary gland most often caused by bacterial infection.

Scientific literature provides some support for the adjunctive use of lysozyme in mastitis, particularly in veterinary medicine (notably bovine mastitis). Studies have shown that lysozyme can inhibit the growth of common mastitis-causing pathogens such as Staphylococcus aureus and Streptococcus species. Its presence in human milk has also been associated with a protective role against infection in the lactating breast, suggesting a physiological relevance.

However, direct clinical evidence in humans for lysozyme supplementation or topical application as a treatment for mastitis is limited. Most human data are indirect, focusing on its natural role in milk rather than as an exogenous therapeutic agent. In summary, while the theoretical and in vitro basis is strong, and animal data supportive, robust human clinical trials are lacking, resulting in a moderate evidence rating.