Ge Hong, also known by the pseudonym Baopuzi, contributed significantly to the future of pharmaceutical medicine. He was the grandnephew of Ge Xuan, who was a Taoist and alchemist of the Three Kingdoms Period. However, it was actually his great uncle's disciple Zheng Yin who introduced Ge Hong to alchemy. He performed many experiments and worked with substances like cinnabar (the most popular alchemy substance of the time), realgar, sulphur, alum, mica, iron, and tin. In addition to these substances, he was also interested in the medicinal value of plants and fungi.