Human saliva is not poisonous. This common misconception often arises from concerns about disease transmission or the potential for infection from human bites. Saliva is a natural bodily fluid that plays several important roles in maintaining oral health and initiating digestion.
The True Nature of Saliva
Saliva is predominantly water, about 99% water, but it contains many other important substances. These include electrolytes like sodium, potassium, calcium, chloride, and bicarbonate, which help maintain the mouth’s pH balance, usually between 6.2 and 7.4. Saliva also contains mucus, which provides lubrication, and various proteins and enzymes.
Enzymes such as amylase and lipase begin the digestion of starches and fats in the mouth. Saliva holds antimicrobial agents like lysozyme, lactoferrin, and secretory IgA, which protect against infections. Saliva also aids in taste perception by dissolving food molecules, protects tooth enamel, and helps clean the mouth by washing away food debris.
Saliva and Disease Transmission
While not inherently toxic, human saliva can act as a vehicle for transmitting various pathogens, including viruses and bacteria. This occurs when an infected person’s saliva comes into contact with another individual, often through direct means like kissing, or indirect means such as sharing eating utensils or drinks.
Many common illnesses can spread this way. Viruses responsible for the common cold, influenza, mumps, and mononucleosis are known to transmit through saliva. Bacterial infections like strep throat can also spread via salivary contact. Hepatitis B and C viruses have also been linked to transmission through saliva, though less commonly.
Risks from Human Bites
Human bites, unlike casual salivary contact, pose a significant risk of infection. This danger stems not from poisonous saliva, but from the diverse bacteria naturally present in the human mouth. When a human bite breaks the skin, these bacteria are directly introduced into the wound, leading to infection.
Bite wounds can lead to serious complications such as cellulitis, a bacterial skin infection, or abscesses, localized collections of pus. More severe infections include osteomyelitis, a bone infection, or septic arthritis, a joint infection. Common bacteria found in infected human bites include Streptococcus species, Staphylococcus aureus, Eikenella corrodens, and anaerobic bacteria. Due to the high risk of infection, any human bite that breaks the skin requires prompt medical attention.