Are there any poisons that lay dormant unless a significant quantity of one has been added, i.e. poison X might as well be water in concentrations less than 5M, but at 6M, all of a sudden a threshold has been reached and the poison has activated.

  • 2
    $\begingroup$ Anything that that the body has a mechanism to filter out fit into this description you pose. If the does was acute and high volume, the poison would overwhelm the body's ability to process and excrete the poison and produce the negative effect. I think you can find more detailed discussion and an actual answer by searching this site. $\endgroup$
    – J. Ari
    Commented Jun 19, 2017 at 1:58
  • $\begingroup$ How about alcohol then? Seems to me it also has some activation threshold until negative effects kick in ; ) $\endgroup$ Commented Jun 19, 2017 at 7:45
  • $\begingroup$ Poisons based on inactivating an enzyme might work like that: as long as there is some critical amount of a vital enzyme left inactivated, the organism could be comparatively healthy. It seems you're writing a murder mystery... $\endgroup$ Commented Jun 19, 2017 at 18:25
  • $\begingroup$ This is pretty much how anything that enters your body works.. even water. $\endgroup$
    – Bob
    Commented Jun 20, 2017 at 23:36

1 Answer 1


Yes, there are certainly some chemicals that are harmless in low quantities but really dangerous in higher doses.

The common painkiller paracetamol (or acetaminophen) is one such candidate. In low doses it is a mild analgesic but in higher does it is deadly. The reason is that there is a metabolic side-reaction in the liver that produces a small amount of a toxic compound. Under normal circumstances this is mopped up by other pathways in the liver and causes no damage. But when large amounts are taken the liver's capacity to mop up the toxin is exhausted, the toxin builds up to dangerous levels and it causes severe liver damage often resulting in death.

  • $\begingroup$ Close, but it's not exactly what I'm looking for, since that would be how the body deals with it rather than the mechanism of the poison itself. $\endgroup$
    – Tzacol
    Commented Jun 20, 2017 at 7:06
  • $\begingroup$ @Tzacol You might struggle to find a poison with those requirements: all poisons depend on how the body interacts with them; you can't separate the effects. $\endgroup$
    – matt_black
    Commented Jun 20, 2017 at 8:37
  • $\begingroup$ Well the question was about the existence of them, if such a thing doesn't exist, then it doesn't exist and I have the answer. $\endgroup$
    – Tzacol
    Commented Jun 21, 2017 at 3:02
  • $\begingroup$ @Tzacol You don't have a useful answer since no poison "exists" except through its interaction with something. So the question is meaningless unless you specify what is being poisoned and how (and, once you specify that context, threshold poisons exist). $\endgroup$
    – matt_black
    Commented Jun 21, 2017 at 8:56
  • $\begingroup$ Seems pretty useful to me. I've got my answer, what I'm asking doesn't exist. $\endgroup$
    – Tzacol
    Commented Jun 21, 2017 at 17:52

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