I think that you're thinking of poisons; the central slogan of toxicology is "the dose makes the poison" [0]. Carcinogens, chemicals which aggravate the chance

I think that you're thinking of poisons; the central slogan of toxicology is "the dose makes the poison" [0]. Carcinogens, chemicals which aggravate the chance of cancer, follow different rules; usually DNA damage is occurring. Some very specific viruses are carcinogenic; not all viruses are. Similarly, some very specific molecules are carcinogenic, but not every substance is carcinogenic in sufficient quantities. An obvious counterexample is water, which is toxic in large amounts but not carcinogenic. [0] https://en.wikipedia.org/wiki/The_dose_makes_the_poison https://en.wikipedia.org/wiki/The_dose_makes_the_poison