As we know, the practice of Chinese herbal medicine contains theory, strategy, formulae and substances. Formulae are inseparably related to strategies. And strategy here refers to the treatment method, which is specific to the pattern of a disorder and its cause.The formulation of a formula and formula choice are based on the treatment principle and strategy.Thus "the Formula is derived from the Strategy, and the Strategy arises from the Pattern". On the other hand since the number of formulae is increasing continuously, the formulae are classified in several groups based on their actions and indications which reflect a certain strategy. This is called "the Strategy unites the Formulae".
The art of using formulae and strategies in Chinese medicine has also undergone changes through the ages. Chen Zhong-Ling, a physician who lived in the Qing dynasty divided all treatment methods into eight strategies, i.e. promoting sweating, emesis, purging, mediation, warming, Heat clearing, dissolving and tonification. 

1. Strategy to promote sweating (Han Fa). To promote sweating is to release the Exterior disorders by perspiration and regulating the Ying (nutrient qi) and Wei (defensive qi) systems. Such formulae as Gui Zhi Tang, for relieving the Exterior disorder of Wind-Cold; Yin Qiao San, for Exterior disorder of Wind-Heat; Jiu Wei Qiang Huo Tang, for relieving the Exterior and removing Dampness; and Da Qing Long Tang, for relieving the Exterior and clearing Interior Heat, represent this strategy.
2. Heat-clearing strategy (Qing Fa). To clear Heat means to treat disorders of Interior Heat by clearing Pathogenic Heat. Such formulae as Long Dan Xie Gan Tang, for clearing excessive Heat and Dampness in the liver and gallbladder; Bai Tou Weng Tang, for clearing Heat in the intestines and Dao Ci San, for Heat in the heart, represent this strategy.
3. Draining downward strategy (Xie Xia Fa). Draining downward (or Purging) is to treat Excess interior disorder by removing the Stagnation or Retention (of food, blood, water, Heat or Cold). This strategy is underlined in such formulae as Cheng Qi Tang, for draining the Heat and relieving constipation; Ma Zi Ren Wan, for lubricating the intestines to relieve constipation and Zeng Ye Cheng Qi Tang for draining and tonification.
4. Mediation strategy (He Fa). Mediation or harmonization means to treat disharmonies between Ying and Wei or Zang- and Fu-organs by regulation and adjustment. This strategy is involved in such formulae as Xiao Chai Hu Tang, for regulating Shao Yang disorders; and Si Ni San for disharmony between the liver and the spleen.
5. Warming strategy (Wen Fa). Warming means to treat Interior Cold by warming Yang. This strategy is involved in such formulae as Li Zhong Tang, for warming the Middle-Jiao and removing Cold, and Zheng Wu Tang for warming Yang and removing Damp.
6. Tonification strategy (Bu Fa). Tonification is to treat Deficiency conditions by reinforcing or strengthening. This strategy is involved in such formulae as Bu Zhong Yi Qi Tang, for reinforcing Qi; Gui Pi Tang, for nourishing blood; and Ba Zhen Tang for nourishing Qi and blood; Liu Wei Di Huang Wan, for nourishing Yin and Jin Gui Shen Qi Wan for reinforcing Yang.
7. Dissolving strategy (Xiao Fa). Dissolving means to treat food stagnation and to disintegrate masses by promoting digestion, by promoting Qi and blood circulation and by removing Phlegm or Dampness. The following formulae represent this strategy: Yue Ju Wan, for promoting Qi circulation; Bu Yang Huan Wu Tang, for invigorating blood; Bao He Wan, for food stagnation; Zhi Sou San, for dissolving Phlegm; Huo Xiang Zheng Qi San, for dispelling Dampness.
8. Emesis strategy (Tu Fa). Emesis means to eliminate Phlegm, stagnated food or toxic substances retained in the throat or stomach by inducing vomiting. Because of the possibility of irritation or impairment of vital-Qi, formulae underlining this strategy are not often used except in some urgent conditions