By listening to the sound of the patients, doctors cannot only detect the changes of the organs related with sound, but also changes of the other internal organs. The sounds include: speech sound, breathing, coughing, hawking (clearing the throat noisily), and belching.

Also, doctors can smell the odor released by patients. It is believed that when viruses attack the human body, people's internal organs and blood will be affected, thus making their body fluid and excreta release a bad smell.

Ⅲ. Interrogation

Using interrogation, doctor will talk to the patients or the patients' relatives (to get the information about how the disease occurs, how it develops, its current symptoms, and how it is treated). This method is useful when there are no obvious symptoms from the patients' outer appearance. In this case, interrogation will help the doctors to get the information they need. Also, by interrogating, doctors can obtain other indirect information related with the disease, such as the patients' daily life, working environment, food preference, and marital status.

Ⅳ. Pulse Feeling and Palpation

Doctors use the method of taking the pulse and palpation by touching or pressing the patient's pulse points. It is believed that changes inside the body are reflected in the changes of pulse activity. Sometimes doctors press the skin of a certain part of the body to identify the nature and the severity of the disease inside the body part.