mandated by Chinese law. Each monograph details the exact herbal ingredients that make up the patent formula, usually accompanied by the specific tests that should be used for correct herb identification, such as thin layer chromatography (TLC) or high performance liquid chromatography (HPLC), the percentage of each ingredient, and specific cautions and contraindications. The monograph also details the manufacturing methods that must be followed, how to process and cook the herbs, often including specific requirements for finished product testing including authenticating and assessing the potency of the formula with active ingredient markers where known, as well as testing for dissolution time and content uniformity. All good manufacturing practice (GMP) certified factories must also test for heavy metal levels and microbials for all patent medicines they produce. However, many patents do not list all ingredients, presumably to protect the secrecy of the formula. An example of this is Yunnan Baiyao, a popular formula used to stop bleeding, whose ingredients have never been revealed. This is an acceptable practice in China, where no other protection exists to protect family or "secret" Chinese herbal formulas. In western countries, there is considerable variation of ingredients and in the proportions of ingredients in products sharing the same name. This is because the Chinese government allows foreign companies to apply for modifications of patent formulas to be sold outside of China. For example, Hebei brand Lifei pills contain Kadsura (feng sha teng) and Morus (sang ye), whereas Plum Flower brand Li Fei Pian contains Schizandra (we wei zi) and Gecko (ge jie) instead. Another example is Qing Qi Hua Tan Wan. The Lanzou brand uses Citrus (ju hong). The Lanzhou Foci Min Shan brand and the Plum Flower brand do not, but use Ginger (sheng jiang). Herbal formulas Chinese classic herbal formulas form the basis of Chinese patent medicine. These are the basic herbal formulas that students of traditional Chinese medicine learn. Many of these formulas are quite old. For example, "Liu Wei Di Huang Wan" (六味地黄丸 liù wèi dì huáng wán) was developed by Qian Yi (钱乙 Qián Yǐ) (c. 1032–1113 CE). It was published in the "Xiao'er Yao Zheng Zhi Jue" (also known as "Key to Therapeutics of Children's Diseases" 小儿药证直诀 xiǎoér yào zhèng zhí jué) in 1119 by Qian Yi's student. Although Liu Wei Di Huang Wan can be prepared as a raw herb decoction (or herbal tea), it was originally created to