From the Wikipedia page 
Shennong (Chinese: t 神農, s 神农, p Shénnóng; Japanese: Shinno, 神農; Korean: 신농, Sinnong; Vietnamese: Thần Nông), which mean "Divine Farmer", also known as the Emperor of the Five Grains (t 五穀先帝, s 五谷先帝, p Wǔgǔxiāndì), was a legendary ruler of China and culture hero reputed to have lived during the time of Three Sovereigns and Five Emperors, some 5,000 years ago.
Shennong is said in the Huainanzi to have tasted hundreds of herbs to test their medical value. The most well-known work attributed to Shennong is The Divine Farmer's Herb-Root Classic (simplified Chinese: 神农本草经; traditional Chinese: 神農本草經; pinyin: Shénnóng běncǎo jīng), first compiled some time during the end of the Western Han Dynasty — several thousand years after Shennong might have existed. This work lists the various medicinal herbs, such as lingzhi, that were discovered by Shennong and given grade and rarity ratings. It is considered to be the earliest Chinese pharmacopoeia, and includes 365 medicines derived from minerals, plants, and animals. Shennong is credited with identifying hundreds of medical (and poisonous) herbs by personally testing their properties, which was crucial to the development of Traditional Chinese medicine. Legend holds that Shennong had a transparent body, and thus could see the effects of different plants and herbs on himself. Tea, which acts as an antidote against the poisonous effects of some seventy herbs, is also said to have been his discovery. Shennong first tasted it, traditionally in ca. 2737 BC, from tea leaves on burning tea twigs, after they were carried up from the fire by the hot air, landing in his cauldron of boiling water.