The title is my question: what organs are absolutely needed (fatal if injured/removed) by the human body and perhaps animals in general?

I'm not asking which organs are mechanically replaceable, but more what organs cannot be removed (and not replaced) in order to maintain human life.


To clarify the question, I'm wondering what organs when removed (and applied no medical intervention) would cause fatal effects in a short amount of time, or cause semi-fatal effects (ex. shortened lifespan). A list perhaps of importance, if possible, would be nice.

note: I have no medical knowledge so I'll leave 'short' open to interpretation.

  • $\begingroup$ well.. i think it is only the brain which has no mechanical replacement as of now. $\endgroup$
    Commented Apr 28, 2013 at 4:52
  • $\begingroup$ @WYSIWYG I've updated my question to clarify. I've been reading in wikipedia that ex. removal of the liver, pancreas is potentially fatal - and was wondering what other organs have the same effect. $\endgroup$
    – dk123
    Commented Apr 28, 2013 at 4:58
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    $\begingroup$ I think you can rather ask which organs are dispensable. easier to answer $\endgroup$
    Commented Apr 28, 2013 at 5:10
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    $\begingroup$ Just to clarify, are we looking for organs that once removed would be fatal without medical intervention? For example the body can be maintained for a long time without kidneys if dialysis is applied. $\endgroup$
    – Rory M
    Commented Apr 29, 2013 at 10:41
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    $\begingroup$ As the comments are gradually illustrating, I think this question is too vague to really be answered effectively. There are some clear examples of organs that can be removed w/o immediately causing death with varying degrees of medical intervention but you could likely keep any small amount of human tissue alive for weeks in the lab so the answer would be all of them except for that piece* (lots of medical intervention required). $\endgroup$
    – DQdlM
    Commented Apr 29, 2013 at 18:36

3 Answers 3


You can't remove most organs. The heart, lungs and brain are the ones that without you'll die in seconds. The rest you'll live a few hours or more. All depends how long you wish to live. The best way to see which organs are most required is to look at the order organs are shut down when there isn't enough oxygen or blood. That tells you which area most and least important.

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    $\begingroup$ +1 Do you perhaps know of a link or source of some sort that covers the shut down list you've mentioned? $\endgroup$
    – dk123
    Commented Apr 29, 2013 at 9:58
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    $\begingroup$ Usually when a person has lost blood they'll lose blood to their skin, followed by muscles (excluding heart/diaphragm), gut (from oesophagus to anus). Meanwhile the blood reserve in the spleen is being mobilised, releasing lots of things to help clot the blood etc. Last to go are lymph nodes (involved in the immune system), liver (similarly involved) then heart and brain closely together. $\endgroup$ Commented Aug 15, 2014 at 8:18

There is a list of "vital organs" on which there is a consensus that if such organs are removed, the body dies within hours/minutes. Yet people can live long with only one lung or one kidney.

Another list could include other organs that are semi-vital: we could live for a relatively long period without them, but their absence has to be compensated with a continuous treatment (pancreas, thyroid, etc.).

In contrast, people can live in "good health" with non-vital organs removed such as legs, eyes, teeth...

  • $\begingroup$ +1 Thanks for the reply and vital organs link, is there perhaps also a source you know that covers the semi-vital organs you've mentioned? $\endgroup$
    – dk123
    Commented Apr 29, 2013 at 9:54

I'm not a medical professional, so this isn't exhaustive or guaranteed 100% accurate:

You can live a (*mostly) normal life without your:

  • appendix
  • tonsils
  • spleen
  • gallbladder
  • pancreas
  • portions of your liver (pieces can be removed and it will regenerate)
  • portions of your small or large intestines
  • both lungs (one is needed)
  • both kidneys (one is needed)
  • uterus
  • testes
  • ovaries

*there are some side effects such as lowered immune function or difficulty digesting fatty foods, but for the most part, you might not even notice.

You can live with some **detriment to your quality of life without:

  • colon
  • bladder
  • up to half your brain
  • stomach
  • thyroid

** surgical interventions can replace the colon and bladder with pouches of intestine, drugs can regulate the loss of the thyroid. Losing half your brain messes up a lot, but it's survivable.

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    $\begingroup$ Can you add at least one reference for this list? $\endgroup$
    – Chris
    Commented Aug 12, 2014 at 22:04
  • $\begingroup$ I could be wrong but the question asks which organs are required for life and not with ones are not too important for it. $\endgroup$ Commented Aug 12, 2014 at 22:07

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