expression
one man's meat is another man's poison
Proverb meaning what benefits one person may harm another; literally 'A's medicine is B's poison'.
彼にはいいアドバイスでも、私には合わない。まさに甲の薬は乙の毒だ。
Even good advice for him doesn't suit me. It's truly a case of one man's meat being another man's poison.
A Japanese proverb using the characters 甲 (first, A) and 乙 (second, B) to contrast two parties, with 薬 (medicine) and 毒 (poison) illustrating opposite effects.