一粒老鼠屎壞了一鍋粥

1. • lit. one pellet of rat feces spoiled the whole pot of congee (idiom)
2. • fig. one bad apple can spoil the whole bunch

Character by character

• 一(yī)one
• 粒(lì)grain
• 老(lǎo)prefix used before the surname of a person or a numeral indicating the order of birth of the children in a family or to indicate affection or familiarity
• 鼠(shǔ)rat
• 屎(shǐ)feces
• 壞(huài)bad
• 了(le)marks a completed action
• 一(yī)one
• 鍋(guō)pot
• 粥(zhōu)congee