I take some medication and vitamin pills every day, and I also take twice a day of some Chinese herb medicine per the order from my wife. The pills are tasteless, while the herb medicine are bitter to swallow. Well, sometimes you have to "swallow a bitter pill." Here is the some usages of said idion as attached below.

【英語世界】良藥苦口利於病 直面真相脫困境 - 教育 - 香港文匯網 (wenweipo.com)