Since getting a new puppy last week I've been asking myself if it's really true that dog saliva has antibacterial properties and, if so, why aren't the components of the saliva being used to make new drugs? Apparently I'm not the only person to ask that. If you look online you see all kinds of forums where someone is wondering the same thing. The question has been the topic of science fair experiments and even the occasional study in more sophisticated research labs. In 1975, Heddle and Rowley found that secretory immunoglobin A (IgA) antibodies, found in dog saliva, had limited antibacteria properties, particularly against the bacterium Vibrio cholerae, that could be used to fight infection in living mice. In 1990, a team from the University of Davis, California reported, in an article in Physiology and Behavior, that limited antibacterial properties in dog saliva, against E. coli and Streptococcus canis, and theorized that mother dogs could prevent infection in their pups by licking the mammary and genital areas. However, a search of the current literature using PubMed actually reveals more reports of infection and illness after letting dogs lick wounds, than any evidence of benefiting from the practice.
Hart and Powell. 1990. Antibacterial properties of saliva: Role in maternal periparturient grooming and in licking wounds. Physiology and Behavior, 48(3):383-386. doi:10.1016/0031-9384(90)90332-X.
Heddle and Rowley, 1975. Dog immunoglobins. II. The antibacterial properties of dog IgA, IgM and IgG antibodies to Vibrio Cholerae. Immunology 29(1):197-208.
Restriction Enzymes: A bacterial defense mechanism