Isekai Yakkyoku

A young pharmacologist and researcher in Japan named Yakutani Kanji died from overworking, and was reincarnated in a parallel world looking like a fantasy medieval Europe.
He was reincarnated as Falma de Medisus, a 10 year old apprentice to a famous Royal Court pharmacist, who had attained an inhuman skills of ability to see through disease, material creation, and material destruction.
In a society in which dubious medical practice are rampant, price gouging through the monopoly of the pharmacist guild and good medicine isn’t available to the commoners he decided to use his knowledge to change the world.
He was recognized by the Empress of the time and got permission to open a Pharmacy at the corner of the town.
He decided to wipe out the fraud that has swept the world, and deliver to the commoners a truly effective medicine that was developed using present day pharmacology.