Since the Han Dynasty (206 BC – AD 220), especially since the Ming and Qing dynasties (1368 - 1911), China has accumulated rich experience in preventing and controlling contagious diseases. According to A History of Plague in China (Zhongguo Yibing Shijian), China has witnessed over 300 epidemics in the over two millenniums since the Western Han Dynasty (206 BC – AD 24). Thanks to TCM, throughout the history of China, there has never been a tragedy in which millions of people died like the 1918 flu pandemic, and the Black Death, which swept across Europe in the 14th century.

Since the founding of the People's Republic of China, TCM has played an important role in containing major epidemics, such as the encephalitis B epidemic in 1956, the SARS outbreak in 2003, and the H7N9 bird flu in 2009. When encephalitis B hit Shijiazhuang in North China's Hebei province in 1954, Pu Fuzhou, a TCM master from the Academy of Traditional Chinese Medicine (the predecessor of the China Academy of Chinese Medical Sciences), used heat-clearing and toxic-removing formulas, such as Baihu Soup and Qingwen Baidu Decoction, to treat patients, which achieved good results. In 1956, when encephalitis B spread in Beijing, Pu adjusted the formulas in accordance with the summer heat and humidity of Beijing and treated patients with humidity-eliminating and heat-clearing formulas, such as Sanren Soup, Sanshi Soup, and Qianjin Weijing Soup, which also recorded good effects. In 2003, when Guangzhou was hit by SARS, the Guangzhou University of Chinese Medicine admitted 74 patients infected with the SARS virus, among which only three cases were treated with hormone therapy, with none of the patients haunted by after effects after recovery.

COVID-19 is a new infectious disease, with no vaccines and specific antiviral drugs against it. It poses a daunting challenge for modern medicine. Novel coronavirus pneumonia causes damage to the lungs. It is different from bacterial pneumonia, which can be cured by antibiotics, and other viral respiratory diseases, which can be prevented through vaccination or antiviral medications. The novel coronavirus is a new pathogen, with its characteristics not fully understood. While patients with mild symptoms can recover with the help of their immune system, most patients suffer lung damage. Those with underlying diseases, such as cardiovascular and cerebrovascular diseases, are at higher risk of becoming severely ill. Improper administration of drugs will cause side effects to the system, fuel a cytokine storm, trigger respiratory distress syndrome, and lead to multiple organ failure, even death. To sum up, the primary difficulty in treating COVID-19 is to curb the overreaction of the immune system, which damages lungs and causes organ failure. The treatments available now can only mitigate symptoms.

So how does TCM inhibit COVID-19? Though TCM is not efficient in inactivating the novel coronavirus during in-vitro experiments, it could improve the immune system of human body, and alleviate inflammation caused by the over response of the immune system. Clinical effects show that TCM can remarkably alleviate symptoms of mild and moderate COVID-19 patients, including fever, coughing, and bodily pain. For severe patients suffering from hypoxia, TCM is able to ease symptoms, including fever, coughing and shortness of breath.

The novel coronavirus invades human cells through a spike-like protein on its surface that attaches to the ACE2 receptor (angiotensin-converting enzyme 2) on the surface of a cell. The ACE2 is like a "knob on door", and the virus "hijacks" the "knob" using its spike-like protein, opening the door into human cells. Studies conducted by Stanford University and the University of Hong Kong suggest that baicalin in scutellaria baicalensis, a TCM herbal ingredient, and hesperetin in dried tangerine peel can combine with ACE2, thus serving as a potential chemical compound for treating COVID-19. A paper published in the journal, Critical Care Medicine, in June suggests that Xuebijing Injection, a TCM medicine, can significantly lower the risk of community-acquired pneumonia, and reduce the time severe patients use ventilators and their length of stay in the ICU.

Each TCM prescription consists of multiple ingredients, whereas a chemical medicine is composed of single ingredient. Each TCM prescription is a complex system and has multiple targets and links in curing disease, but that also makes it difficult to illustrate its function mechanism clearly and completely in a short time.

Life is a complex phenomenon. What we know about it is a tip of the iceberg. Many puzzles about essence and rules of life can't be solved using a linear approach. According to Western science, TCM has no clear function mechanism, is subjective in judging curing effects, and its diagnosis and treatment based on overall analysis of the patients are not in line with the development process of chemical medicines covering "basic experiment, clinical trials, approval, and application", thus being labeled as not scientific. TCM is typical of traditional Chinese culture and science, and boasts a complete theory system. Unlike Western medicine, which follows the route of first getting developed in laboratory and then being applied to patients, TCM is the knowledge Chinese people have summarized from practices throughout the ages. Though many effects can not be explained scientifically, such as Huoxiang Zhengqi Liquid, which can cure indigestion-caused diarrhea, a fact widely known among Chinese people, we need to attach great importance to the use of TCM.

We can observe life from outside to inside, from macro to micro, or from factors such as climate and psychological influence. When understanding the etiology and pathogenesis, we should consider biological factors such as bacteria and viruses, but also pay attention to the immunity and self recovery of the human system. Both Western medicine and TCM have their own strengths. TCM is good at regulating the system holistically and in curing epidemics, chronic disease and helping recovery. As Yuan Zhong, a professor at Peking Union Medical College, said, the understanding of life and disease prevention and treatment is like scaling a mountain. One can climb from the sunny slope, or from the shady slope. Only when we reach the top of the mountain can we enjoy a panoramic view of both sides of the mountain. Western medicine and TCM are like the two slopes of the mountain.

The author, Tang Xudong, is a senior researcher with the China Academy of Chinese Medical Sciences.

The article is translated by Ma Chi.