What happens when someone takes an anti-venom for an animal they weren't bit by, either for incorrect identification of the animal they were bit by or if they weren't bit at all?

I am looking for the immune system reaction, and possibly why it reacts as it does.

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    $\begingroup$ @jonsca Why the edit to change antivenom to antivenin? From Wikipedia: "The name "antivenin" comes from the French word venin, meaning venom, which in turn was derived from Latin venenum, meaning poison. Historically, the term antivenin was predominant around the world, its first published use being in 1895.[2] In 1981, the World Health Organization decided that the preferred terminology in the English language would be venom and antivenom rather than venin and antivenin or venen and antivenin." $\endgroup$
    – Alan Boyd
    Nov 3, 2013 at 18:49
  • $\begingroup$ @AlanBoyd Feel free to roll back. I was always taught that "antivenom" was incorrect. $\endgroup$
    – jonsca
    Nov 3, 2013 at 18:55
  • $\begingroup$ It seems like there's a mixture of both in the literature, and Webster's defines "Antivenom" as "Antivenin". I will leave it be, though. $\endgroup$
    – jonsca
    Nov 3, 2013 at 19:12
  • $\begingroup$ @jonsca I searched for both words as title terms at Web of Science: antivenin has total hits 190, 104 (54.7%) since 1981 whereas antivenom has total hits 598, 561 (93.8%) since 1981. It looks like the WHO decision was pretty influential. Incidentally I have no axe to grind on this, I was just curious since I don't recall ever seeing the word antivenin before your edit. $\endgroup$
    – Alan Boyd
    Nov 3, 2013 at 19:35
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    $\begingroup$ usually the antivenoms are antibodies raised against these protein based venoms. Serum injections may cause anaphylactic reactions but should otherwise be safe. $\endgroup$
    Nov 4, 2013 at 4:42

1 Answer 1


Although it is fancy to think of antivenom as a poison for the poison, technically it is a poison only for the poison!

Antivenom is developed in horses (equine) by hyperimmunizing them against the particular venom at a non-lethal dose, followed by collecting the serum. Venoms are complex and have many enzymes and hence are proteins. So, antivenoms are just antibodies against the venom proteins.

Moreover, the antivenoms are classified into monovalent and polyvalent. This signifies whether the sera was prepared by hyperimmunizing the animal with the venom of a single species or many common venomous snake species together.

Usually, a snake bite is an emergency and the victim or the attendants rarely identify the snakes (In our place, patients sometimes to our surprise, even bring the killed snake to the casualty!). Hence, to avoid confusion polyvalent sera are used.

I've written all this just to make an impression that polyvalent sera also carry antibodies against the wrong snake too, but at the end of the day, it's the right antibody that does the job.

As mentioned in the comments, apart from occasional anaphylactic reactions or serum sickness, they are pretty safe (cost/benefit) to use.


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