We often talk about spleen-stomach deficiency, but do you know why it becomes deficient? Many people think it’s caused by dietary habits, such as overeating or a preference for raw and cold foods. A beginner in Traditional Chinese Medicine might tell you it’s due to irregular diet, while a more intermediate practitioner might attribute it to dampness obstructing the spleen. Medicines like Guipi Wan or Sijunzi Tang can temporarily relieve symptoms such as a thick, greasy tongue coating and poor appetite, but once you stop taking them, the problem returns. Why is that? Because dampness is merely a manifestation of spleen-stomach deficiency, not the true underlying cause.

In the Five Elements theory of Traditional Chinese Medicine, Heart Fire generates Spleen Earth, their relationship akin to that of mother and child. Heart Fire is like the sun, and Spleen Earth is like the earth; the sun shines upon the earth, enabling it to thrive. However, modern lifestyle habits—such as staying up late, constantly scrolling through phones, daily anxiety and internal turmoil, and excessive indulgence in cold things—are like constantly pouring cold water on the sun, extinguishing the Heart Fire. When Heart Fire is not vigorous, the spleen-stomach, this “earthen stove,” naturally cannot warm up properly. It’s like the soil of the Loess Plateau; it appears barren, but in reality, it’s because of insufficient sunlight—the land doesn’t receive enough energy.

People with spleen and stomach deficiency often have cold hands and feet, along with a thick and greasy tongue coating. The underlying cause is actually insufficient heart yang. Heart yang is like a fire within the body—when the fire is not vigorous, the "small boiler" of the spleen and stomach cannot function properly.

What makes things worse is that many people, upon realizing their spleen and stomach are not functioning well, think about consuming spicy foods to stimulate themselves and warm up their bodies. This is akin to using a blower to vigorously fan a basket of nearly extinguished charcoal embers. On the surface, it may seem as if the fire has become a bit more vigorous, and the body temporarily feels warmer. In reality, however, this only accelerates the depletion of the remaining embers—a typical case of drinking poison to quench thirst—and will only weaken the spleen and stomach further.

I once encountered a patient, Lao Li, who had suffered from spleen and stomach deficiency for many years. He usually had cold hands and feet, a tongue coating so thick it looked like a layer of white frost, and a poor appetite. After hearing that spicy foods could expel cold, he often ate hotpot and spicy hot noodles. At first, he felt warm and comfortable after eating. However, it wasn't long before he noticed his spleen and stomach issues worsening—not only did his appetite deteriorate further, but he also frequently experienced diarrhea. When he came to see me later, I immediately recognized his condition as insufficient heart yang and told him that forcefully stimulating heart yang with spicy foods would only backfire.

In fact, ancient masters of traditional Chinese medicine understood this principle well. Zhang Zhongjing’s Zhigancao Decoction, while superficially regulating the heart meridian, is actually nourishing the yang qi of the spleen and stomach. Li Dongyuan also proposed that when tonifying the spleen and stomach, herbs that promote yang must be included. However, nowadays, out of ten spleen-strengthening formulas, nine neglect to nourish heart fire.

The true path to regulating spleen and stomach deficiency lies in nourishing heart yang. For instance, bask your back in the sun at noon, allowing the sun's yang energy to directly replenish your body. Practice standing meditation (zhanzhuang) after waking up in the morning to regulate breathing and promote smoother circulation of qi and blood, which also nurtures heart yang. Soak your feet in warm water before going to bed at night to enhance blood circulation and "add firewood" to heart yang.

The "Golden Mirror of Medicine" states: "When the sun shines brightly overhead, the dark mists disperse naturally." Heart yang is like the sun; as long as it is abundant, the dampness in the spleen-earth will naturally dissipate, eliminating the need to blindly focus on removing dampness. When Sun Simiao treated spleen and stomach disorders, he always included mildly diuretic and dampness-resolving herbs. This is because of the interplay of the five phases: excess causes harm, and regulation brings balance; the organs in the body mutually constrain and maintain equilibrium. The brilliance of Zhang Zhongjing's use of medicine lies in his ability to identify the true root cause of illness.

"The Yellow Emperor's Inner Canon" states, "Treating disease must seek its root," and the root of spleen and stomach deficiency lies within the beating heart's fire. To properly regulate the spleen and stomach, we must first nurture the heart's yang. This is the fundamental method of treatment.