From the Iranian traditional medicine point of view, Mizaj (temperament) represents the excess or lack of warmness and humidity in one's body and is classified based on four qualities of warmness, coldness, dryness and wetness.

Warmness 

Warmness is the quality which causes vibrancy, movement, and exuberance. Just as adding heat energy to water increases the speed and motion of the molecules and causes the molecules to move a little further apart those with warm Mizaj are livelier, more extrovert, move briskly and talk faster. Consuming food stuff with warm characteristics would also stimulate such moods. 

Coldness

Coldness is a quality characterized by stillness, silence, and frigidity. Like cooling a liquid decreases the speed of molecules and bring them closer together those with cold Mizaj are less active, slow, more introvert, more patient and calmer. Consuming food stuff with cooling characteristics such as yoghurt would bring about such moods as well.

Dryness

Dryness is a quality that provides objects and phenomenon with stability and let them assume shape. It is represented with wrinkles, thinness and shrinking similar to green wood which is left to be dried or fresh fruits which will turn dried after some time. People with dry Mizaj are also thin, have a sturdy frame, and dry and wrinkled skins. They behave in a rigid way and don't usually change their mind. They have unshakable and firm beliefs. Consuming food stuff with drying characteristics such as salt, pepper and vinegar would intensify such moods.

Wetness

Wetness is a quality which encourages flexibility and fluidity, and increases volume very similar to making soft clay out of clay. People with wet Mizaj are normally fat and have squishy bodies. They are normally flexible and can endure hardships. They can easily put up with different people. Consuming food stuff which are high in water content such as citrus fruits, dairy products and lettuce or topical products such as violet or almond oil would also evoke such moods.

As explained previously while the main or inherent Mizaj (the one that a person is born with) is forming one or two of the four qualities of warmness, coldness, dryness, and wetness might become dominant and decide the main Mizaj.

Therefore, regarding which quality is more dominant the tempers are classified totally into nine categories of warm, cold, wet, dry, warm and dry, warm and wet, cold and dry, cold and wet, and moderate (when none of the qualities are dominant).

Seyed Mahdi Mirghazanfari, MD, holds a PhD degree in medical physiology and is an Iranian-Islamic traditional medicine researcher. He is also an assistant professor in AJA University of Medical Sciences, Tehran.

MQ/M