The World Health Organization estimates that between 65 to 80 percent of the world’s population (over 4 billion people) rely on western medicine compared to only 10 to 30 percent of people who use traditional chinese medicine (TCM). While TCM and western medicine are similar in their purpose, they differ in their principles and techniques. TCM and western medicine has a similarity in the purpose of using medicine. They are both a system of health care. Although they use different approaches to treat patients, the ultimate goal is to help patients reduce pain and rehabilitate them with their medical knowledge. They are aiming to create a harmony in the human body. The first difference between TCM and western medicine is the principle. TCM treats a person as a whole. Some people would choose having chinese medicine not only they are ill but also want to be well. Conversely, western medicine treats symptoms. Furthermore, TCM is more about the supernatural phenomenon, whereas western medicine requires scientific knowledge. For instance, the fundamental concepts in TCM are Qi(chi), yin, and yang that are invisible. Qi is usually defined as vital energy in the body. Yin and yang are used to understand complicated relationships in the body, and they are opposite to each other in the world. For example, summer is hot, so it is yang; winter is cold, so it is yin. Yin and Yang have to exist at the same time. If the world doesn’t have the summer heat, plants can not grow vigorously; if it doesn’t have a cold winter, plants can not grow up in the next spring time. Therefore it is important to distinguish whether this symptom is yin or yang because a wrong judgement can aggravate the illness. In western perspective, it is more important to demonstrate the knowledge of anatomy, pathology, chemistry, etc.Another significant difference is the methods of diagnosis. There are four diagnostic methods, questioning, inspection, auscultation-olfaction, and palpation. A TCM doctor diagnoses patients based on the integration of all diagnostic methods. Questioning is inquiring patients about their conditions. Doctors would usually have additional questions based on the information provided by the patients. Inspection is practitioners observe patients’ spirit, skin color, form( movement and posture), tongue. Observation of the tongue is helpful for physicians when confirming diagnosis because it is relating to heart and lungs. Different parts of the tongue represent different internal organs, and a normal tongue is pale red with a thin whiting coating(moss on the tongue). Auscultation is listening to the patient’s, cough, breath, speech, and olfaction is to know the smell emitted from the patient’s body. Palpation might be the most important method to diagnose the patient because it reflects the condition of lung, spleen, and kidney. Western medicine makes diagnosis through physical examination. Scientific instruments are the most common method to examine the human body. Doctors would confirm the case base on the collection of all evidences. In conclusion, traditional chinese medicine has a similarity in their purpose but also different in either principle or diagnosis methods. Their different principles provide an explanation of  their advantages and disadvantages. For example, TCM stands for treating the root from the problem, so it could lead to a slower process than western medicine. Although western medicine is directly target to the pathogen, it sometimes can bring significant side effect. Recently, number of doctors are attempting to merge TCM and western medicine. While using western medicine, people can combine with traditional Chinese medicine and acupuncture to accelerate recovery. It will be a breakthrough to promote the integration of traditional Chinese medicine and western medicine in the future.