Yin and Yang are opposites which depend upon each other for their existence. There would be no Yin without Yang and Yang without Yin. Think of the Chinese symbol for Yin and Yang. Half is light, half is dark and the two curl around one another. In the Yang part of the symbol there is a spot of dark (Yin) and in the Yin part of the symbol there is a spot of light (Yang).

Yin translates from Chinese to English literally as, "?shady place, north slope (hill), south bank (river); cloudy, overcast'. Yin is female. Yin is characterized by sadness, darkness and passiveness. Yin corresponds to night and is often depicted by water.

Patients with an excess of Yin feel cold. They will have cold hands and/or feet, their face will appear white, they will move slowly, their heart rate will be slow, they will not be thirsty, they will not sweat, they will have much clear urine that is odorless, and their tongue will be covered with a white coating.

For a Yin related disease the Chinese herbal practitioner will order heat to be applied to specific areas of the body. He will prescribe warm/spicy food, warm drinks and warm herbs. 

Yang translates from Chinese to English literally as, "sunny place, south slope (hill), north bank (river); sunshine". Yang is male. Yang is characterized by light, happiness and activity. Yang corresponds to day and is often depicted by fire.

Patients with an excess of Yang feel hot. They will have hot skin, they will sweat profusely, they will be extremely thirsty, their urine will be infrequent and be a dark color with a strong odor, their movements will be quick and nervous, and their tongue will have a red or yellow coating.

For a Yang related disease the Chinese herbal practitioner will order cold baths, cold food, cold drinks, and cool herbs.