Potion Uri no Shounen: Kare no Potion wa Jitsu wa Nandemo Naosu Densetsu no Elixir deshita

A boy created and sold potions intended to treat minor ailments, though he was unaware they were in fact the legendary elixir capable of curing all injuries and diseases. After a noble girl, unable to walk due to a severe and untreatable illness, is healed by his potion, his remedies gain sudden popularity. People from all walks of life, including adventurers and nobles, begin to seek out his elixir. His life takes a new turn as word spreads about the miraculous effects of his accidental creation.