Shen Nong, venerated as a Taoist god and in Chinese folk religion is regarded as the founder of natural medicine and agriculture. He developed the art of cultivating the Five Grains (hemp, millet, rice, wheat, ad pulse) and besides that he was the first to analyze the beneficial and harmful properties of herbs by testing them on himself. He is said to have a transparent stomach and whatever he ate could be observed. He often nearly died from his tests, and he did too finally when he had too much of a poisonous herb which made him turn black. That is why he is depicted as a blackish deity, dressed in leaves and grass only since he lived in times before civilization.
His statue is often found on altars, like this one in Taiwan.