How to say "toxicity" in Japanese

• 毒性どくせいCommon
  nounThe common word for toxicity proper: how poisonous a substance is, in scientific and medical discussion. It also covers virulence, the degree to which something is poisonous.
  それは毒性どくせいのある化学かがく物質ぶっしつが含ふくまれていた。↗

  It contained harmful chemicals.
• 毒質どくしつ
  nounFrames toxicity as the toxic property or quality of a thing. A less common word, and rarely the one you want: for toxicity as such, 毒性 is the usual choice.
• 有害性ゆうがいせい
  nounMeans harmfulness: the quality of being damaging or injurious, whether or not a true poison is involved. Choose it when English 'toxicity' really means how harmful something is.
• 毒気どっき
  nounRefers to a poisonous ingredient or poisonous nature — poison as something present in a thing. A less common word, and seldom the one you want for 'toxicity'; 毒性 is the usual choice.

Use 毒性 as the usual word for toxicity, especially of substances; 有害性 when you mean harmfulness rather than poison; 毒質 and 毒気 are less common alternatives centered on poisonous quality or nature.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 毒性どくせいtoxicity
• 毒質どくしつtoxic property
• 有害性ゆうがいせいharmfulness
• 毒気どっきpoisonous ingredient