Dong Demao advocated the theory of spleen and stomach, dating back to classic works such as Neijing, Difficult Classics, Synopsis of the Golden Chamber, Treatise on Febrile Diseases, and down to Jin, Yuan, Ming and Qing Dynasties. He learned from others, learned from Shi Jinmo's innovative spirit, and combined with his rich clinical experience accumulated for many years, gradually formed a unique theory of spleen and stomach.

Dong Demao believes that Chinese medicine is a unique feature and advantage of China's medical and health undertakings. The so-called characteristics are that for China, there are Chinese medicine and western medicine, and Chinese medicine is the characteristic of Chinese medicine; The so-called advantage is that for foreign countries, generally speaking, the advantage of western medicine is abroad and the advantage of Chinese medicine is at home.

Connecting ancient and modern times, focusing on the spleen and stomach, regulating qi-flowing, and combining treatment and nursing: diagnosing the disease outline and grasping the main symptoms. In the treatment of diseases, clearing exogenous pathogens, regulating internal injuries of the spleen and stomach, paying attention to the internal and external relations of the human body, emphasizing "external dredging and internal smoothing", "internal circulation of qi, external and internal harmony", paying attention to the whole, syndrome differentiation and treatment, and supporting the pile for difficult diseases have achieved remarkable results.

Dong Demao combined typhoid fever with febrile diseases, especially praised Liu Hejian's theory that "all six qi can turn into fire" and Ye's argument that "warm pathogens are affected by diseases, and the lungs attack first". He inherited Huangdi Neijing, Treatise on Febrile Diseases and Treatise on Febrile Diseases, inherited Shi Jinmo's academic thought and clinical experience, and combined with his own experience, gradually formed the academic thought of clearing exogenous diseases.

Dong Demao's method of regulating spleen and stomach is the concrete application and development of spleen and stomach theory. In particular, Zhou Shenzhai said that many diseases can't be cured, but many people can be cured if they find the spleen and stomach. It is considered that spleen and stomach diseases should be divided into deficiency and excess, spleen excess and stomach excess. The clinical condition is complex, often mixed with excess and deficiency, and both cold and heat are treated. Ten methods of regulating spleen and stomach were summarized, among which attacking, regulating qi, clearing away heat, eliminating dampness and promoting digestion were the methods, and supplementing qi, lifting, warming middle warmer, astringing and nourishing yin were the supplements. According to the specific clinical symptoms, each method is divided into several methods or a combination of several methods, so the outline is flexible. He advocated harmony in the prescription, emphasizing that the dosage of spleen and stomach diseases should be light, the medication should be refined, the serious illness should be light, and the curative effect should be clear. It is recommended to use stagnation tonics with caution to prevent qi stagnation, and to use bitter cold with caution to avoid damaging stomach qi. He often said: "If you don't cut the sky, you can't cut it." Pay attention to the influence of liver on spleen and stomach, and make good use of the method of soothing liver and regulating spleen. He believes that the content of Neijing with students is extremely rich and should be inherited and carried forward. At the same time, spleen and stomach diseases are easy to cure and relapse, so in order to consolidate the clinical efficacy, patients must be guided to take care of themselves. He studied qigong theory, summed up the arguments of "three treasures of essence and spirit" and "concentrating on regulating qi", and practiced the 16-character formula, that is, "calming the heart and sitting quietly, forgetting things and caring for each other, and breathing naturally", which was applied to clinical treatment and mental adjustment and fell ill many times.

Good at acupuncture and combination of acupuncture and medicine: Dong Demao is good at acupuncture and has profound attainments, insisting on the combination of acupuncture and medicine, and is known as the "golden needle Dong Demao" in Beijing and Tianjin. Proficient in Chinese medicine theory, good at internal medicine, pediatrics and acupuncture. He is a famous Chinese medicine expert and acupuncturist in China.

Cultivate students and pass them on: Dong Demao is rigorous in his studies, seeking truth from facts, making friends with teachers, saving the rich and helping the poor, and saving countless people. He worked tirelessly and assiduously, trained five graduate students successively, and completed the teaching task of the first batch of apprentices in China despite his illness. After his death, the students compiled his experiences into Dong Demao's Experience Collection of Internal Medicine.