I was thumbing through my wife’s Real Simple while I ate lunch. I don’t need the beauty tips, since I already look marvelous, but I am always on the lookout for new recipes. I saw the headline Watch Your Tongue. The opening paragraph notes

“The tongue can be a key diagnostic tool.”

Which is sort of true. A diagnostic tool? Yep. Key? No way.

At the end of my long and storied career, I fancied myself a diagnostician. Any primate can look up how to treat an infection. Many primates do not bother, part of why I had a practice. But you need a proper diagnosis before you can look up, much less start the correct treatment, of a disease. Since infections can involve any organ and since infections can mimic non-infectious diseases and vice versa, I always had to keep an eye out for alternative reasons for the patient’s problems. The diagnosis might be something boring i.e. not an infectious disease.

Diagnosis is usually made from the history and labs. The patient has their story — and it is a story, an often unfocused, rambling, filled with pointless digressions and leaving out important information story — from which you glean the pattern of their illness. It always pissed me off when a patient would tell me to read their chart rather than listen to their history. For one thing, I never trusted what others put in the chart if it concerned my consultation. I always assumed everyone else on the case had no idea what was really going on. They almost always did know what was going on, I worked with a bunch of great HCWs, but it is an approach that will occasionally save me from mistakes. As the Russian proverb noted, Don’t trust. Verify. But more importantly, it is the pattern of the illness, obtained from the history, is what is likely to give the needed information to make the right diagnosis.

Then, you confirm that diagnosis with diagnostics such as blood work, biopsies, and x-rays.

So how helpful is the exam? It can be fun to find disease manifestations, but is rarely diagnostic. My pulmonary attending as a resident, said, only quasi-humorously, the lung exam is what you did while you were waiting for the CXR to develop. Physical findings are more of a hint or a confirmation of what diseases the history suggests, moving them up and down the differential diagnosis, doctor speak for the list of possible diseases for a given presentation. As an example, if there is no heart murmur, a valve infection is less likely. Unless it is on the pulmonic valve, which you are unlikely to hear. Or the disease is so early that a murmur hasn’t developed. Or the valve has been completely destroyed so no soil in which to grow a murmur. My father, a cardiologist, was hard of hearing towards the end of his career. I asked him how he heard subtle murmurs. He said, “What?” I repeated the question louder and he replied, “That is why we have echocardiograms.”

That is the problem with the physical exam. Each organ has a finite number of potential manifestations, if any, for a disease process, and is unreliable. More often than not, the exam doesn’t help one way of the other in deciding what the diagnosis is. Almost every finding on exam has several possible causes and the history is what guides you to interpreting the physical findings.

Like the tongue. There are a smattering of diseases that can manifest in the tongue. As an infectious disease doctor, there were the manifestations of AIDS, the rare tongue ulcer, an occasional manifestation of disseminated histoplasmosis, and my favorite, the strawberry tongue of toxic shock diseases. It really does look, but not taste, exactly like a strawberry. Oddly, no one has ever figured out why the toxin results in a tongue that looks like a strawberry.

I always found the skin and eyes to be better organs to examine for hints of the underlying diagnosis, but in the vast majority of patients, the eyes, skin, and tongue were, as we said, WNL. Within Normal Limits, not We Never Looked. Old joke.

So why the tongue to

infer a lot about a patient by examining their tongue- hydration level, coffee or tobacco use, immune health and vitamin deficiencies.

All reasonable inferences from the tongue. But not really all the helpful and not all the much information gained. A dry mouth might mean a lack of water, but could be a sign of scleroderma. You can ask about coffee and tobacco consumption for a more accurate idea of use, B6 and B12 deficiencies will have tongue findings, but they are not specific. A bit of thrush might suggest AIDS, but there is a broader differential diagnosis for fungal tongue involvement. Again, the history and the labs will be more useful in determining what the cause of a given tongue finding will represent.

Unless. Is there more to the story as to the vital nature of the tongue beyond taste and rudeness? Except in Mongolia?

Oh, yes. Traditional Chinese Pseudo-Medicine (TCPM). They quoted Dr. Michelle Loy, an acupuncturist and specialist in Integrative Medicine at Weil Cornell Medicine in New York, who offers many a SCAM (Supplements, Complementary and Alternative Medicine). In TCPM

the tongue is considered the gateway to our bodies.


So I thought this would be a good opportunity to review one of the foundational fictions upon which TCPM is based and the ‘diagnoses’ that it renders. TCPM is based upon a huge number of medical fictions, reflecting the size and antiquity of Chinese society. So I will only discuss a small sliver of this vast system, the tongue.

One of the important diagnostic procedures in TCPM is an examination of the tongue. All the organs map to and manifest on the tongue. As does the feet, the hands, the ears, the top of the head and the entire body. Although no mapping to the buttocks. Yet. I can’t see where the body has room for all these different connections; perhaps it is the real cause of obesity.

And to make it confusing, there are two forms of tongue mapping. The triple burner where the tongue is divided into thirds

The tip of the tongue corresponds to the Upper Burner (Heart, Lungs); the middle corresponds to the Middle Burner (Stomach, Spleen), and the base of the tongue corresponds to the Lower Burner (Kidneys, Bladder, Intestines.

and there is the Zang fu method

The tip of the tongue corresponds with the Heart, the region at the front of the tongue between the tip and the center corresponds to the Lung, the center corresponds with Stomach and Spleen, the right side corresponds to the Gallbladder, the left side corresponds to the Liver, and the base of the tongue corresponds to Kidney, Bladder, Large Intestine, and Small Intestine

Whose tongue mapping reigns supreme? No one cares; it’s like trying to decide which of the innumerable styles of acupunctures is the right one. All of them. Of none. Take your pick. At least TCPM is consistent. Just as there are no acupoints or meridians on the genitals, I cannot find where the genitals map to the tongue. No, I am not going to for the obvious rude commentary. You people. Grow up.

So TCPM practitioners look at the tongue for

tongue color, tongue quality, tongue fissure, tongue fur, red dot, ecchymosis, tooth mark, saliva, and tongue shape are identified for each tongue

and, depending on the constellation of the above, make a diagnosis. Mind you, it is a TCPM diagnosis, not a diagnosis as understood by anatomy and physiology of reality-based disease. A fictional understanding of disease can only lead to a fictional diagnosis.

All the above tongue findings can also be a manifestation of a real systemic disease, except for teeth marks. I can’t see how tongue teeth marks could be a manifestation of a real disease. Seizure disorder maybe. TCPM practitioners are not looking for a real diagnosis.

It is important to remember that the TCPM diagnoses made have nothing to do with understanding modern anatomy, physiology or disease. These changes are manifestations of the fictional diagnoses of TCPM. These changes in the tongue diagnose qi stagnation or damp retention or a variety of other nonsensical diagnoses unhinged from reality.

So one of the many modalities of TCPM is to examine the tongue based on a fictional understanding of disease to come to a fictional diagnosis. Then they apply a fictional therapy, like cupping or acupuncture.

Not surprisingly when the SCAM is not based on reality, the diagnostic modality is not reproducible:

TCM tongue inspection for specific characteristics examined was not a reliable diagnostic method, at least for the group of TCM practitioners involved in this study.

And there are several other studies that show TCPM practitioners can’t agree on a TCPM diagnosis, such as Damp Heat Retention, after tongue examination.


The average agreement of the diagnoses provided by 3 TCM practitioners was at the same low level as previously reported. No association was found between the diagnostic methods used and the consistency of diagnosis

But that is what happens when you are essentially making up stuff as you go along

Here is the weird thing, to my understanding, about TCPM, is they keep trying to apply these traditional fictions of diagnosis and treatment to modern understanding of anatomy, physiology and disease. If they can’t agree on a TCPM diagnosis, you want to turn them loose on diabetics?

It is a curious literature.

For example, they tried to see what TCPM would add to the diagnosis of coronary artery disease.

Qi deficiency was the most popular syndrome in patients with CHD (87.1%), blood stasis syndrome and phlegm retention syndrome took the second place, accounting for 79.9% and 78.7% respectively. No significant difference was shown in comparison of tongue and pulse figures with the affected branches of coronary artery, the dark-pale tongue with white greasy fur and taut-slippery pulse being the dominance in patients. The blood-lipid levels in patients with various TCM syndrome types were similar, showing insignificant difference.

Conclusion: The TCM pathogenesis of CHD takes qi deficiency as the core, blood stasis and phlegm retention as the important pathologic products.

One author notes

However, due to its qualitative, subjective and experience-based nature, traditional tongue diagnosis has a very limited-application in clinical medicine. Moreover, traditional tongue diagnosis is always concerned with the identification of syndromes rather than with the connection between tongue abnormal appearances and diseases. This is not well understood in Western medicine, thus greatly obstruct its wider use in the world.

Maybe its lack of wider use is due to the fact that TCPM diagnostics and diagnoses are useless.

But since TCPM practitioners don’t know a burro from a burrow, let a computer do it. There are several studies where they used photos of tongues and had a computer examine them to diagnose, say, breast cancer or gastric cancer or diabetes.

I do not know what to make of these studies. A one level, that of TCPM, they are a waste of time. But, AI and computer learning applied to the tongue, or some other organ, could very well yield diagnostic hints of diseases independent of its underlying TCPM approach. The computer can sometimes see patterns humans can’t. They could inadvertently be on to something. Blind pigs and acorns and all that.

If computer analysis of tongues is successful, I am sure that TCPM will see it as a justification of their fictional medical system. Nope. Just got lucky.

At some point I likely discuss pulse diagnosis, while you are waiting check out Harriet Hall’s piece from 2017.


The picture is of our English bulldog, Pugsly. He is a rescue, someone’s COVID pet, and when we got him around age 2 (the dog, not me) he had been ill-used, we think mostly ignored. His qi was badly blocked at several points and he had an excess of heat and stagnation. As you can tell from his tongue, all that has been resolved and he is a happy, drooling, flatulent, and quite delightful, dog. Even if I agree he is an

abomination of nature cursed with high rates of miserable health problems.

Not unlike TCPM.



  • Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at

Posted by Mark Crislip

Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at