Normally there is no abnormal odor in the healthy people whose visceral functions are normal and circulation of blood and qi is smooth. Under pathological conditions, the visceral functions are affected, qi, blood and body fluid are encumbered and fumigated by pathogenic factors, or the transportation and transformation of food and water become abnormal, giving rise to the production of strange odor. So smelling the patient’s body and the excreta is helpful for understanding the pathological changes.

Attention should be paid to different odors so as to understand their nature. Generally speaking, slight stinking odor or odor without foul smell indicates asthenia syndrome, cold syndrome or cold-dampness syndrome. Heavy stinking or foul odor indicates sthenia syndrome, heat syndrome or dampness syndrome. Sour and putrid odor usually suggests retention of food. Blood smell suggests bleeding disease. Putrid odor suggests ulceration and sore.
 
In differentiating odors, attention should be paid examine the source of odors so as to decide the location of the disease. And syndrome differentiation should be made in the light of the difference in odors.
    
Foul breath:
Foul breath is seen in oral diseases, such as caries. Foul breath is usually due to stomach heat. Sour odor from the mouth indicates retention of food; putrid odor from the mouth suggests internal abscess.

Sputum and snivel odor:
Stinking and foul sputum with pus and blood is usually seen in exuberance of heat toxin or accumulation of heat toxin into lung abscess. Odorless thin sputum and snivel are usually seen in exogenous disease due to wind cold. Frequent discharge of foul and thick snivel suggests nasosinusitis due to lung heat or damp-heat in the gallbladder meridian.

Body odor:
Foul and putrid body odor suggests ulceration and sore. Bromhidrosis is due to fumigation by damp-heat.

Odor of feces and urine:
Clear urine without stinking odor indicates asthenia and cold syndrome, also seen among healthy people. Scanty reddish and stinking urine indicates downward migration of damp-heat. Loose and stinking stool suggests asthenia-cold in the spleen and intestines. Sour, putrid and foul odor of stool or foul flatus indicates retention of food and indigestion.

Menstruation odor:
Thin and stinking menorrhea and leukorrhea indicate asthenia-cold or cold-dampness syndrome. Yellowish thick and foul leukorrhea is due to downward migration of damp-heat. In dealing with leukorrhea with stifling foul odor, cares should be taken to exclude the possibility of cancer.