What precautions should be observed in the usage of herbs that release the Exterior?
First of all, since herbs that release the Exterior are pungent and their tendencies of action are ascending and dispersing, especially with the herbs that can cause sweating, overdose may disperse the Qi too much, consume the Yin of the body and cause other complications. In patients who are deficient in Yin or Qi owing to their constitution, chronic disease, stress or dietary habit, these herbs should be used with caution.
Furthermore, as pungency also has the property of movement, these herbs should also be used with caution in bleeding conditions or in pregnancy.
Secondly, the dosage of herbs should be adjusted to suit the condition of the individual, the syndrome and the season. For elderly people, children, and people with a weak constitution and for mild syndromes, in a gentle climate and in the summer, the dosage should be reduced.
For adults with a strong constitution and for severe syndromes, in a cold winter or a cold place, the dosage should be increased. If sweating must be induced, the dosage is adjusted according to the syndrome.
A mild sweat over the whole body is required. Heavy sweating must be avoided because it can only weaken the Qi and Yin. In the third place, as eliminating Wind-Cold or Wind-Heat is not generally difficult, these herbs should not be used for a long period of time.
A dosage of 3 days is recommended to treat Exterior syndrome. If the exogenous pathogenic factors have not been removed completely, then another 3-day dosage can be prescribed. With regard to herbs that may cause heavy sweating, the dosage and treatment course should be adjusted according to the reaction of the patient after each use.
