The four qi and five flavors constitute a theoretical framework in Traditional Chinese Medicine for studying the properties of medicinal substances. It analyzes the functional characteristics of medicinals through their natures of cold, hot, warm, and cool, and their flavors of sour, sweet, acrid, bitter, and salty. Later generations further developed the theory of meridian tropism, enriching the pharmaceutical theory of Chinese medicine. However, today we will not discuss these profound and abstruse theories, but rather address topics closely related to the daily lives of ordinary people—that is, the things we eat and use every day, and what properties they possess from the perspective of Chinese medicine, and what effects they have on our health.

　　In fact, in the view of Chinese medicine, there is no absolute boundary between food and medicine. For example, when a patient presents with generalized fatigue, listlessness, a sunken epigastrium, splashing sounds in the stomach, and a thin, rapid pulse, what medicine should be prescribed? If the pattern differentiation cannot be determined, and the patient then says, "I'm hungry," even a fool would know to bring a bowl of rice rather than decocting Eight Treasure Decoction (Ba Zhen Tang). No matter how well ginseng and angelica tonify qi and blood, they cannot match four taels of rice in terms of corresponding to the pattern. In this sense, how is food not also medicine? Other examples include seaweed treating goiter and brown rice treating beriberi—these are all common household foods, yet they cannot be easily replaced by other medicinals. Therefore, food does not simply provide us with nutrition; in reality, it has an immeasurable potential influence on people's health.

　　Unfortunately, people's knowledge of food is truly very limited, and most of it is confined to the conclusions of Western medicine. But Western medical methods often suffer from considerable one-sidedness. They excessively emphasize isolated components such as protein, sugar, and vitamins, while lacking any description of the comprehensive characteristics of food. Within the limited space available today, this article lists some everyday foods, including some daily-use materials, describing their Chinese medical properties, in the hope of providing a reference for those who care about health.

　　[Rice]: Neutral in nature, sweet in flavor. It can nourish the stomach, generate fluids, and boost qi. There are no fewer than several hundred varieties of rice; here we discuss only its general characteristics. Different varieties differ slightly in their effects. In my experience, Thai fragrant rice seems to be superior in its stomach-nourishing effect. Some people believe that early-season rice has better nutrition, but in fact, early-season rice is slightly hard in texture—those with strong stomachs have no problem with it, but those with weak stomachs should avoid it. Late-season rice is soft in texture and more suitable for those with weak stomachs, but its nature is relatively greasy and cloying, which some people do not particularly like. Glutinous rice is even more stagnant and cloying, yet it has the function of tonifying the spleen and benefiting the lungs. Chinese medicine has a formula called "Lung-Tonifying Donkey-Hide Gelatin Decoction" (Bu Fei E Jiao Tang), which contains glutinous rice. On the market one can also find "jingmi" (round-grained rice), which has a crystalline texture and looks beautiful. Jingmi has an especially good stomach-nourishing effect, is not too cloying, and also has the effect of generating fluids. People with poor spleen and stomach function can use it to cook congee, adding Chinese yam, lotus seeds, jujubes, and so on—this is a good method of regulation and tonification. Although there is plenty of rice nowadays, its fragrance is in fact much inferior to that of the past. After all, the heavy use of chemical fertilizers has diluted the inherent inner quality of the rice itself. Good rice possesses an intrinsic rice fragrance; the stronger the aroma, the more authentic it generally is.

　　Nowadays, living standards are rising daily, and the dining table often features many dishes but little rice. Superficially this seems to enhance nutrition, but in fact rich flavors instead harm the stomach. Moreover, when nutrition exceeds the body's needs, it becomes phlegm-damp turbidity lurking within the body, becoming a hidden danger for future illness. Furthermore, as far as the concept of "nutrition" is concerned, whatever meets the body's needs is nutrition; otherwise it might as well be called dregs. In this sense, rice is the best nutrition. Among its forms, rice congee has the best stomach-nourishing effect—no medicine under heaven surpasses it. 　　 　　Additionally, because the nature of rice is extremely mild and balanced, it has an excellent regulating effect on all kinds of cold-heat disharmony, internal wind and external toxins, disharmony of visceral qi, and insufficiency of nutritive and defensive qi. Health comes from balance, and stomach qi is the fulcrum of balance. Therefore, I urge everyone to attach great importance to stomach qi, and to the food we eat every day: rice.

　　[Wheat]: Neutral in nature, sweet in flavor. However, compared with rice, it is slightly accompanied by damp stagnation. Therefore, it is generally ground into flour and made into wheat products for consumption; if fermented, it is even more conducive to digestion. Its power to nourish the stomach and generate fluids is slightly inferior, but its effect of boosting qi and filling out the physique is superior. Thus, northerners have stronger physiques and greater vigor than southerners. Generally speaking, those with good stomach qi are better suited to eating coarse grains and wheat products, while those with weak stomach qi are better suited to eating refined grains and rice. In addition, various instant noodles are now popular; having undergone drying processes, not only can they not nourish the stomach, they actually damage it. Of course, occasional use can awaken the spleen and stimulate the appetite (Chinese medicine says: "The spleen likes dryness; the stomach likes moisture"), but they must not be eaten regularly. Dried foods can never be considered truly nutritious.

　　[Purified water]: Chinese medicine attaches great importance to "water." In the Materia Medica of Foods (Shi Wu Ben Cao), more than one hundred kinds of "water" are listed. The functions of water are none other than moistening the fluids; good quality water can also nourish yin and subdue fire, and promote the flow through the channels. But purified water is one of the most unnecessary dietary inventions of this century, although it may have great uses in other respects. Because water is inherently cold in nature, most of it must be heated to boiling before drinking. The heating process, first, reduces its cold nature and, second, kills its unclean components. The molecular chains of heated water differ structurally from those of unheated water. Therefore, although purified water has been filtered of other components, in terms of its nature it displays coldness. In essence, it is still raw water, and long-term consumption is detrimental to the body's qi transformation. Once a patient asked me: "Why do I still get abdominal pain and diarrhea from drinking purified water?" In fact, it is caused by its inherent coldness not having been dispelled. As the saying goes: "Water that sits for ten days becomes poisonous water." Although purified water has been filtered of bacteria, with long-term storage, its stagnant nature is likely only to increase rather than decrease. Therefore, I recommend that everyone drink heated water.

　　[Cooking oil]: There are many kinds of cooking oil, but their common function lies in nourishing the "fluids" (ye). The function of the fluids leans toward moistening the body's bone marrow, brain, joints, skin, hair, and so on. Humans consume considerably more oil than other animals, which is why the human brain is more developed than that of other species. In terms of nourishing effect, tea seed oil is the best, followed by lard (though nowadays pigs are all raised on industrial farms, so the quality of their fat has greatly declined), then rapeseed oil; cottonseed oil and palm oil should not be consumed in excess. Oils are mostly warm in nature; only lard is slightly cool. Good quality oil also has a slightly sweet taste. Oils have positive significance for enhancing the body's vitality, warmly tonifying the ministerial fire, and strengthening qi transformation. However, the nature of oil belongs to turbid, rich qi, which is unfavorable for the circulation of clear qi; excessive intake easily leads to internal accumulation of damp-heat, blockage of the channels, generation of phlegm and transformation of fire, and can also disturb one's temperament. Therefore, the principle of moderation is especially emphasized.

　　[Salt]: Salt is cool in nature and flavor; its action tends toward inward contraction and downward sinking, and it enters the nutritive level