If I cut my finger, can I put it in my mouth and suck it?

"Your finger is injured, put it in your mouth and suck it."
"I heard that saliva can be used for disinfection, and it works."

I don’t know when it started (maybe we learned it from watching TV dramas, after all, in TV dramas, people always cut their hands when cutting vegetables), but when our fingers or other parts of our bodies are injured, we will subconsciously put them in our mouths and lick them, thinking that this can disinfect and sterilize and help prevent wound infection.

So, does saliva really have this effect? ​​Can saliva kill bacteria, disinfect, and prevent infection?

Let's first look at the composition of saliva.
Saliva has a complex composition

Saliva is one of the most complex fluids in the human body. It is mainly secreted by three pairs of large salivary glands, namely the parotid gland, sublingual gland, and submandibular gland, as well as many other small salivary glands, with a secretion rate of about 0.5 ml per minute. When the glands are stimulated by external factors such as eating, hunger or lack of water, saliva secretion increases.

The amount of saliva secreted by humans in a day and night is about 1000 to 1500 ml, most of which is actively or passively swallowed into the stomach for reabsorption to maintain fluid balance.

The composition of saliva includes water, organic components and inorganic components, and water accounts for more than 99% of all the components of saliva.

The inorganic components in saliva are mainly composed of a variety of strong and weak ions, including Na+, K+, Cl-, Ca2+, etc. Their main function is to help maintain the acid-base balance of saliva, maintain the osmotic pressure in the body, and promote the perception of taste.

The organic components in saliva are mainly proteins and other enzymes, including amylase, lipase and mucin. Different enzymes are involved in the chewing, tasting and swallowing of food in the mouth. For example, amylase is involved in the initial digestion of starch in the mouth, and lipase plays a certain role in the perception of oil taste and texture.

In addition, saliva also contains a small amount of lysozyme and growth factors. Lysozyme is an important nonspecific immune factor in the body, which has the functions of antibacterial and anti-inflammatory, improving immunity, and inhibiting the growth of exogenous microorganisms.

Biologically active substances such as epidermal growth factor, fibroblast growth factor, erythropoietin, etc. have certain effects in promoting cell growth and angiogenesis, which is why the oral mucosa has a faster renewal and metabolic rate than other tissues.

It seems that the cleansing effect of the large amount of water in saliva and the sterilization effect of lysozyme have a certain effect on wounds. Does that mean we can use saliva to treat injuries?

——Of course not, and it is definitely not allowed.
Why can't we use saliva to disinfect wounds?

First of all, the main function of saliva is to help form food boluses by moistening food, promote swallowing, protect the oral mucosa from mechanical damage, and play a role in the initial digestion of food through the presence of amylase and other enzymes.

Secondly, the secretion of saliva is affected by many factors, including a person's age, eating habits, drug intake, living habits, etc. It varies from person to person and is not fixed, making it impossible to accurately and continuously "disinfect and sterilize" saliva.

More importantly, the content of lysozyme and growth factors in saliva is extremely small, and it can only be used for simple treatment when medical treatment is inconvenient, and the wound must be small and superficial. Once the wound is deep and involves the subsurface tissue, it may be harmful.

At the same time, the oral cavity is one of the areas in the human body with the highest density and most types of microorganisms. Oral microorganisms include bacteria, fungi and viruses, among which bacteria are the main ones. These microorganisms are colonized in the oral cavity, restraining each other, depending on each other, and living in peace. Once they leave the colonization site, they may become pathogenic and even aggravate the infection of the wound.

(Warning: Some special wounds, such as cat or dog bites, and wounds pierced by rusty nails, must be vaccinated after standardized disinfection and bandaging to prevent rabies virus and tetanus clostridium infection.)
Treating wounds is not just about disinfection

It should be noted that wound healing is not simply a matter of disinfection and sterilization.

While preventing infection, the wound and its surroundings need to be kept clean. When treating the wound, it is necessary to clean the wound correctly according to the nature and location of the wound to reduce secondary damage. When bandaging the wound, the right size, clean and comfortable dressing should be selected. In addition, it is best not to put pressure on the wound or stick it too tightly to avoid obstructing blood circulation.

If the wound shows symptoms such as watery exudate, rot and odor, bleeding and pus, or does not heal for a long time, you should go to the hospital for diagnosis and treatment in time; if you experience shortness of breath, high fever, palpitations, rapid pulse rate, headache and nausea, or the wound does not heal for a long time, you should go to the nearest hospital for treatment as soon as possible.

At present, there is no scientific evidence to prove how effective and advantageous saliva is for wounds, how long its effects last, and how to avoid the risk of infectious diseases.

It is inevitable to have abrasions and bruises in our daily lives. We cannot simply put them in our mouths and lick them and be done with it. We must clearly realize that no matter the size or depth of the wound, timely and correct medical treatment is required to make the wound heal faster and better, and to avoid causing more serious consequences.

Source: Tadpole Musical Notation, Science Popularization China

Reviewer: Wu Xinsheng, deputy chief physician of the Department of Gastroenterology, PLA 371 Hospital