The Chinese traded twice as much tea to the English in return for the herb sage, which was not native to them. Many herbalists feel herbs work better when they are from the local area, because they have the same energy qualities and patterns as the people living in that area. Herbal energetics is another concept that helps determine which herb is right, and much time has been devoted to classifying herbs this way. Once again TCM is in the forefront, but a few herbalists today have taken the time to classify some of our western herbs. Basic energetics determines if an herb is warming, cooling or neutral.
People have their own energetics, too.
If an individual feels cold, needs several blankets on the bed, and has cold hands and feet he will not be helped by herbs that will cause further cooling, like dandelion or echinacea . Similarly, if a person is always warm, wears short sleeves even in freezing temperatures, has a red or ruddy complexion or angers easily, warming herbs like ginger and red pepper should be avoided. Of course, these are generalizations and small amounts of these herbs in combination with other herbs to balance the energetics of an entire formula would still be appropriate. This is what a herbalist should know in order to help clients. This is what few medical professionals who have been trained allopathically even consider.