Chinese prescription is composed of Chinese medicinals according to "seven compatible relations" and "sovereign, minister, assistant and courier" principles.

The medicinals in a formula or prescription have different roles. Some medicinals play a sovereign role, called sovereign medicinals; some play a minister role; some play an assistant role; and some have a courier role, as illustrated in Fig. 16-2. And occasionally some play a counteracting role.

Sovereign medicinal* is the ingredient (medicinal) that provides the principal curative action on the main pattern or primary symptom. Minister medicinal* is the ingredient that helps strengthen the principal curative action of the sovereign medicinal. Assistant medicinal* treats the combined pattern, relieves secondary symptoms or tempers the action of the sovereign ingredient when the latter is too potent. Courier medicinal* directs the action of the medicinals in the formula to the affected meridian or site or mediates other medicinals. And counteracting assistant* is an assistant ingredient with a property opposite to and with a therapeutic effect complementary to the sovereign ingredient.

A clay pot or earthen jar is recommended, not a pot made of iron. Immerse the medicinals in water for half an hour so as to make their medicinal components easily dissolved in the solution and then start to decoct the medicinals. The fire should be controlled based on medicinal properties. Aromatic herbs are decocted with a strong fire until the solution is boiled for several minutes, then a slow fire follows until the decoction is done. Nourishing medicinals, since they are greasy, are decocted with a slow fire, since the effective factors are not easily decocted out.

Some medicinals may need to be decocted first*; some may need to be decocted later*; some may need wrap-decoct*; and some may even need to be decocted separately*. Medicinal ejiao (Colla Corii Asini) needs to be melted into the decoction, and mangxiao (Natrii Sulfas) is usually taken after the powder is dissolved into the decoction.

Like medicinals, formulae can be categorized into many classes. Exterior-effusing formula* is a class of formulae that are composed of exterior-releasing medicinals, and have diaphoretic*, muscle-releasing and eruption-promoting effects, used to treat exterior patterns. Emetic* formula is another class that induces vomiting, used for treating phlegm syncope*, food accumulation, and ingestion of poisons. Interior-attacking* formula is mainly composed of purgatives* with bowel-moving, heat-purging, accumulation-attacking and water-discharging effects, used for treating interior excess patterns. Exterior-interior releasing* formula eliminates pathogens from both the exterior and interior parts of the body, indicated in the treatment of dual disease of the exterior and interior. Harmonizing and releasing formula can adjust functions of the body, indicated in the treatment of lesser yang disease, liver-spleen disharmony, and cold-heat complex patterns. Qi-regulating formula regulates and normalizes the flow of qi. Blood-regulating formula is a group of formulae that correct blood pathologies, including blood-tonifying formula, blood-activating and stasis-resolving formula, and hemostatic* formula. Dampness-draining* formula is composed of dampness-draining diuretics, used to treat exuberant dampness. Dampness-dispelling* formula has the effect of resolving dampness, removing water, relieving strangury* and draining turbidity, used for the treatment of water-dampness ailments. Phlegm-dispelling* formula is used for expelling or dissipating phlegm. Vision-improving formula is used in the treatment of eye diseases. Formula for menstruation and childbirth* is used to treat menstrual disorders, leukorrheal* ailments and obstetric* diseases.