The idea that herbs can be heating or cooling is often connected with traditional Chinese or Ayurvedic medicine. Many people do not realize that this classification of herbal remedies was also a vital part of Western medicine for almost 2,000 years.
Formalized by the Greek physician Galen (est. 130 to 200 CE), herbs were traditionally applied therapeutically to correct various degrees of cold and heat.
Herbs graded as hot in the first degree induce a gentle heat to the body, correcting a natural tendency to coldness or helping a body cooled accidentally or by inclement weather. They are invigorating and reduce pain caused by cold. Valerian, licorice, burdock, camomile, and cleavers are examples of the herbs typically included in this category.
Those herbs hot in the second degree are somewhat stronger and are used for obstructions, such as colic, and to open the pores of the skin. Most of our traditional culinary herbs such as thyme, rosemary, and fennel exhibit this degree of heating.
Third-degree heating herbs, such as angelica and ginger, will cut through tough obstructions and cause abundant sweating.
The fourth degree is so hot that the herbs can burn the body, cause inflammation, or even raise blisters externally, if inappropriately consumed or applied. Garlic, mustard, onions, cayenne, and black pepper were included here, and these are the herbs we most often associate with heat today.
In a similar way, herbs cold in the first degree correct unnatural heat. They moderate heat in the liver, and helpa weak stomach digest food. They are used in mild fevers,or to restrain heat in the bowels. Comfrey, beets, violet,rose, yarrow, and many of the bitter herbs are cold in the first degree.
Herbs cold in the second or third degree should only be used by people who have strong stomachs and hot livers, according to Galen. They were used to close the pores, prevent fainting, and reduce high fevers. Plantain, dandelion, purslane, lettuce, cucumber, citrus fruits, and apples are all considered cold in the second or third degree.
Herbs cold in the fourth degree were reserved for stopping desperate pain; they included the opium poppy and most of the very poisonous herbs.
Galen was careful to point out that applying a herb of the wrong degree might heal the original problem, but would certainly lead to another.
Another Traditional Way to Categorize Herbal Remedies is Through Taste:
Sweet: nourishes, tones, and harmonizes
Spicy: removes stagnancy
Bitter: stimulates, strengthens, and expands
Salty: balances the nerves and moisturizes
Sour: cleanses and regulates