For centuries, a common belief has persisted that dog licks possess healing properties for human wounds. This notion is widespread, often seen as a natural way for a dog to show affection. The idea that a dog’s saliva could mend injuries is a deeply ingrained cultural perception.
Understanding the Belief
The enduring belief that dog licks can heal wounds likely stems from observations of animals instinctively licking their own injuries, which can help remove debris and may offer some soothing effect. Historically, cultures have attributed curative powers to dog saliva, with sayings like the French “Langue de chien, langue de médecin” (“A dog’s tongue is a doctor’s tongue”) reflecting this sentiment. While this behavior in animals is a natural response, it is a self-soothing action that also removes dirt from a wound. Despite these historical perceptions and the comforting nature of a dog’s affection, scientific evidence does not support dog licks as a safe or effective method for human wound healing. Any perceived benefit is generally outweighed by significant risks, particularly for open wounds.
Components of Dog Saliva
Dog saliva is a complex biological fluid containing proteins, enzymes, mucins, and electrolytes. It includes enzymes like lysozyme, which breaks down bacterial cell walls, and lactoferrin, which inhibits harmful bacteria by binding iron. Histatins, small proteins in dog saliva, may promote wound healing and have antifungal properties.
However, dog saliva also harbors a diverse community of bacteria. Common bacteria include Pasteurella canis and various Capnocytophaga species, such as Capnocytophaga canimorsus. The oral microbiome of dogs differs significantly from that of humans, meaning that foreign pathogens can be introduced to a human wound through licking.
Potential Dangers of Licks
Introducing dog saliva to an open human wound carries significant risks due to the bacteria present in their mouths. Infections are a primary concern, even from minor licks. Pasteurella multocida and Pasteurella canis are common bacteria in dog saliva that can cause infections, leading to symptoms like pain, swelling, and redness. These infections can progress to more severe conditions such as cellulitis.
A particularly concerning bacterium is Capnocytophaga canimorsus, a normal part of the oral flora in dogs. While infections from Capnocytophaga canimorsus are rare, they can be severe and life-threatening, particularly for individuals with weakened immune systems, those who have had their spleen removed, or individuals over 40. Infection symptoms can include flu-like signs, blisters, fever, and gastrointestinal issues. If the bacteria spread into the bloodstream, it can lead to sepsis, a severe, potentially fatal condition characterized by widespread inflammation, organ failure, and in some cases, gangrene. Zoonotic diseases, transferable from animals to humans, can also be transmitted through dog saliva.
What to Do for Wounds
If a dog has licked an open wound, immediate care is important to minimize infection risk. Begin by thoroughly washing the wound with mild soap and clean running water. After cleaning, apply an antiseptic solution. Keep the wound covered with a clean, sterile dressing or bandage to protect it from further contamination. Observe the wound closely for any signs of infection, such as increasing redness, swelling, warmth, pain, or pus or discharge. If any of these signs develop, or if the wound is deep or large, seek medical attention promptly. Professional medical advice and good hygiene are crucial for effective wound healing and preventing complications.