I heard a rumor that there were health benefits from giving blood. (The rumor claimed that doing so would help to "remove unwanted stuff from your bloodstream" so that your body could create fresh new blood.)

Is there any truth to this?

[Let me add: I was in Britain during a mad cow disease incident, so I'm not permitted to donate blood to help other people. I'm just trying to understand if there's any health benefit for donating blood for me personally.]

  • No, this is scientific nonsense. What is problematic is the dilution of "unwanted stuff" and that doesn't decrease when donating a part of the whole blood. The "unwanted-to-wanted" ration stays the same.
    – Narusan
    Sep 23, 2017 at 17:24

1 Answer 1


This "rumor" is initially mostly based on a humor. According to humorism your four juices might be out of balance or gone bad and that might prescribe a course of the ancient practice of bloodletting to restore that balance, giving you a cure for almost anything.

Since modern medicine largely abandoned humorism as a theoretical framework this line of reasoning is no longer regarded as valid. If someting in your blood 'is bad', simply reducing the volume of it by loosing blood for this purposeusuallyisn't beneficial at all. This historical detour is mainly directed towards the explanation given to you.

Modern medicine can still name you a quite useful list of benefits, reasons and explanations, but they seem to be more accurate than the ancient views:

  1. You are doing something good to help others, being a benefactor usually makes you feel good. An inherent health benefit. You might have saved a life. or three.

  2. You get a health checkup, since nobody wants blood that doesn't meet certain standards, like not being infectious.

  3. And the first direct benefit you will get: it is quite beneficial for conditions associated with too much iron, like in reducing iron-overload (which can be quickly reached through certain foods or misuse of supplements) or even real diseases like hemochromatosis (Obviously, anyone having iron deficit is excluded from benefiting. Males being the the main target for this potential benefit. But unexpectedly also beneficial for you if you have e.g. certain infections like with Staphylococcus aureus of the antibiotic-resitant kind.)

  4. Quite a surprising result in a study (that needs replication): Back to past leeches: repeated phlebotomies and cardiovascular risk

    BMC Medicine, Michalsen et al. demonstrated a dramatic improvement of blood pressure, serum glucose and lipids after removing 550 to 800 ml of blood in subjects with metabolic syndrome.

  5. And: One more health benefit of blood donation: reduces acute-phase reactants, oxidants and increases antioxidant capacity:

    CONCLUSIONS: These findings suggest that blood donation affected oxidative status and acute-phase reactants in donors. Blood donation removes oxidants and decreases oxidative stress by elevating antioxidant enzyme such as superoxide dismutase. This is one more health benefit or reason why we should donate blood. Further large-scale studies should evaluate this mechanism and compare the same effect of wet cupping therapy.

Summing that up: go and donate (if you are accepted)!

  • It sounds like the rumor I heard was based on your points (4) and (5), and the summary is that they need replication.
    – Dan B
    Oct 1, 2017 at 23:09

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