What Is Tongue Coating? Telling the Tongue Apart from Its Coating

Farzollah Gholizadeh and Fariba Bayrami

One of the most interesting and most overlooked parts of examining the tongue is the tongue coating — the layer on top of the tongue.

Many people look at the colour of their tongue, but don’t know that what really matters is where that colour comes from .

What is tongue coating?

Tongue coating is a layer of cells, bacteria, food debris and other substances that builds up on the surface of the tongue’s papillae.

A thin, limited coating is normal. A “completely clean tongue” is not the measure of health.

6 things to look at when reading tongue coating

In traditional medicine, it is not only the colour of the coating that counts. The practitioner looks at:

• Thickness: Is it thin or thick?
• Moisture: Is it dry or moist?
• Stickiness: Does it clean off easily, or is it sticky?
• Spread: Does it cover the whole tongue or only part of it?
• Colour: Is it white, yellow or another colour?
• Regrowth: Does it come back quickly after cleaning?

Two people can both have a “white tongue”; but if these six features differ, so does their meaning.

The key distinction: the body of the tongue or the coating?

Suppose two people both have a yellow tongue:

• In the first person, the body of the tongue itself has changed colour.
• In the second person, the body is almost normal, but there is a yellow coating on top .

In terms of reading signs, these two situations don’t mean the same thing. The same goes for whiteness and other colours.

One of the most important skills in examining the tongue is asking:

What is the colour of the tongue itself, and what is the colour of the coating?

This small difference can sometimes change the reading completely.

What affects the colour of the coating?

The colour of the coating isn’t always about the internal organs. These can also affect it:

• Bacteria in the mouth
• Oral hygiene
• Dry mouth
• Tea, coffee and coloured foods
• Smoking
• Some medicines

That is why looking at the tongue in the morning, before eating, drinking or brushing your teeth, gives a fairer comparison.

The traditional medicine view

In Avicennian–Greek medicine, tongue coating is considered one of the most important indicators of digestion . According to physicians of the past, when digestion isn’t working properly, the effects can show in the quality of the tongue.

For example, a thick, moist, white coating is read differently when it comes with cold, dampness, a feeling of heaviness and digestive complaints. A yellowish coating with dryness, thirst and a feeling of heat may draw attention to the state of yellow bile.

But none of these is read on its own ; they are read together with the body’s other signs.

Frequently asked questions

Should tongue coating be cleaned off?
Gently cleaning the tongue is part of oral hygiene and can reduce bad breath. But if there is a constant, thick coating, it is also important to understand why.

Is tongue coating a sign of a stomach problem?
It can be linked to digestion, but on its own it does not mean a stomach disease.

Does a yellow coating mean a liver problem?
No. A yellow coating can have many causes; on its own it does not indicate liver disease.

Conclusion

Tongue coating is one of the body’s small but meaningful signs. To read it correctly, look at its thickness, moisture, spread and colour — separately from the body of the tongue .

For all the signs of the tongue and mouth, read our article “The Tongue and Mouth: A Mirror of Digestion and Inner Health” .

If you want to learn the body’s sign language step by step, Dr Kalan’s book “Elaim & Delail” and the online course “ “Reading the Body’s Signs” (in Turkish) will guide you.

This article is for information only and does not replace medical diagnosis and treatment.