thuốc đắng đã tật, sự thật mất lòng

Etymology

 * ultimately based on a line from .

Phrase

 * 1)  bitter medicines ease ailments, the truth offends
 * 2) effective medicines tend to be bitter, and the truth tends to hurt

Usage notes

 * Usually used to say "the truth hurts", but the first half can also be used to convince others to take unpalatable medicines.
 * Although this phrase is the etymological form, it's more commonly seen in variants such as or.