poisonous substance; toxic substance
General term for any substance that is harmful or lethal to living organisms. Used in scientific, medical, and everyday contexts.
A toxic substance leaked from this factory.
Food products containing poisonous substances were recalled.
毒物 is a broader term for 'poison' or 'toxic material', while 有毒物質 specifically emphasizes the substance as a chemical or material that is toxic.
有害物質 means 'harmful substance' and includes non-toxic hazards (e.g., carcinogens, irritants), whereas 有毒物質 is specifically poisonous/toxic.
Compound of 有毒 (yūdoku, 'toxic, poisonous') + 物質 (busshitsu, 'substance, matter').