百害あって一利なし

ひゃくがいあっていちりなし

all pain, no gain; doing no good and a lot of harm; having no redeeming features; being a complete disadvantage

Also written 百害あって一利無し

Meaning

exp
all pain, no gain; doing no good and a lot of harm; having no redeeming features; being a complete disadvantage; a hundred harms and not a single gain

Example sentences

たばこは百害あって一利なし。

Smoking does much harm but no good.