noun
cure-all; panacea
A medicine or remedy believed to cure all diseases; often used figuratively for a universal solution.
この薬は万病薬と言われているが、実際には万能ではない。
This medicine is said to be a cure-all, but in reality it is not a panacea.
Compound of 万病 (all diseases) + 薬 (medicine). The exact historical origin is uncertain, but the word follows a common Sino-Japanese pattern for naming a universal remedy.