Why does my tongue have teeth marks?

A tongue takes the print of the teeth when it is a little too big for the mouth. It rests against them all day and all night, and the edge keeps their shape, like a thumb pressed into dough. So the question the tradition asks is not about the teeth at all. It is why the tongue is swollen, and its answer is water: fluids that should have been moved on have stayed, and filled it.

The organ it holds responsible is the spleen, which in Chinese medicine is less the organ on an anatomy chart than the work of turning food into qi and moving fluids where they should go. A tired spleen moves them slowly; they gather; the tongue fills. That is why the scalloped edge so often comes with tiredness after meals, loose stools, a heavy body and a sweet tooth. And it is why modern teaching adds a caution: a faint scallop on a tongue of normal colour and size, with nothing else, can simply be the shape you were born with.

The Neijing never mentions teeth marks. What it gives is the reasoning later physicians applied to them, in three lines. The first is the rule that fluids and swelling are the spleen’s business.

The second is what happens when the spleen fails at it: what the stomach has taken in is not carried on, and the body, fed but not nourished, weakens by the day.

The third is why the mouth is where it shows. The spleen, the Lingshu says, opens at the mouth.

The Qing tongue readers put the pieces together. Ye Tianshi, whose talks on warm-heat his students wrote down in the eighteenth century, reads a coat that stays moist in someone who feels stifled as the spleen swamped with damp, and a tongue too swollen to put out as damp with heat behind it.

Four pictures. The colour of the tongue and its coat usually decide between them.

• Warm, cooked food, and nothing iced. The spleen, in the tradition, likes warmth and dryness and dislikes cold and damp, so iced drinks and raw salads are the first thing a scalloped tongue gives up.
• Less of the sweet, the dairy and the fried. They are what the tradition calls damp-making, and a tongue already holding water holds more after them.
• Seven parts full, 七分饱. A tired mover given a large meal leaves more of it unmoved.
• Ten minutes of walking after meals, 饭后百步走. Movement is how the tradition shifts fluids that will not shift themselves.
• Meals at the same hours. The tradition counts irregular eating among the things that tire the spleen, as much as what is eaten.
• Photograph the tongue in daylight on the first morning and again a month later. The scallops change slowly, and a comparison is worth more than a mirror every morning.

None of that is a promise, and we make none. Warm, less and walking is the floor for every picture on this page.

• Poria 茯苓, cooked into congee until it vanishes, for every picture here: bland, which in the tradition means it drains.
• Job’s tears 薏苡仁, cooked with the rice, for the two damp pictures, and for the red one above all, since it is cool as well as bland.
• Ginger 生姜, fresh, in the cooking, for the two pale pictures: it warms the mover. Not for the red tongue.
• Tangerine peel 陈皮, a piece in hot water after meals, for the thick-and-greasy picture: it unsticks what the damp has stuck.
• Chinese yam, 山药, steamed or in soup, for the pale-and-soft picture: the gentlest of the foods the tradition gives a tired spleen.

Four finger-widths below the kneecap, a thumb’s width outside the shin bone, is Zusanli, Stomach 36, 足三里: the stomach channel’s great point, which the old rhymes give to everything of the belly. Thumb pressure, a minute each side, after the evening walk; not over varicose veins or a painful, swollen calf. It is not a needle and it is not a claim about outcomes.