Recently I read in an article

The mechanism of fever appears to be a defensive reaction by the body against infectious disease. When bacteria or viruses invade the body and cause tissue injury, one of the immune system’s responses is to produce pyrogens. These chemicals are carried by the blood to the brain, where they disturb the functioning of the hypothalamus, the part of the brain that regulates body temperature. The pyrogens inhibit heat-sensing neurons and excite cold-sensing ones, and the altering of these temperature sensors deceives the hypothalamus into thinking the body is cooler than it actually is. In response, the hypothalamus raises the body’s temperature above the normal range, thereby causing a fever. The above-normal temperatures are thought to help defend against microbial invasion because they stimulate the motion, activity, and multiplication of white blood cells and increase the production of antibodies. At the same time, elevated heat levels may directly kill or inhibit the growth of some bacteria and viruses that can tolerate only a narrow temperature range

Now usually as soon as we realise that we have fever, we immediately take antipyretics, eg. Paracetamol. Now it will cool the body temperature. Isn't this dangerous and wrong?

My question is regarding fever due to infections only.

  • Have you tried researching the negative impact of fever as well?
    – Thomas
    Commented Jul 28, 2020 at 10:32
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    @Thomas, yes I have. According to this article, infectious fevers are beneficial and non infectious fever are harmful. However my question pertains only to the infectious fever. Though I have edited the question to make this point. Thank you for pointing this out Commented Jul 28, 2020 at 15:44
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    I was considering the fact that there are negative side effects to fever caused by infections as well.
    – Thomas
    Commented Jul 28, 2020 at 16:05

2 Answers 2


In normal patients fever can reduce our efficiency or comfort for doing work. For mild infections one may wait for the fever to get over and let our immune response do their job.

For early and effective treatment we prefer antibiotics with antipyretics as antibiotics can do their job alone and fever might not be necessary here. It will give early response than giving antipyretic alone or letting fever be alone.
The other point is that, we prefer antibiotics with antipyretics because the organism inflicting it may cause more damage to our body before getting killed by immune system and thus increasing morbidity and mortality.

Fever is not the only mechanism to fight infection, some people take antipyretics alone which reduces fever and provides comfort but our immune system alone is effective enough to curb some mild infections, so people who take antipyretics alone are not in too much danger but it may prolong the illness in some cases. It is not the general prescribed method and antipyretics should be used with indications like other drugs and not for fever per se (though this reference is for the pediatric population but in general practice, antipyretics are generally not given alone for infections and the same argument can be applied)

For some common viral fevers only conservative treatment is required. Antipyretics are given if temperature is too high because in that case its benifit can outweigh the effects of having fever, otherwise we must let fever to happen recognising the fact that fever is beneficial or not is still controversial (considering the fact that fever in this case can be benificial.)

Finally, there can be many other indications for the use of antipyretic to reduce fever, not just considering a simple argument that it can enhance the immune response eg. paracetamol is given in dengue fever or antipyretics are given to prevent febrile seizures. So I recommend taking antipyretics under the prescription of the concerned medical professional only.

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    So in the nutshell can we say that antipyretics shouldn't be taken immediately and especially without doctor's consultation. Since they are over the counter drugs. As one will not know how bad the infection is or whether the fever is severe or mild just by measuring the temperature? Commented Jul 30, 2020 at 12:11
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    @Pj30 Some people do keep the knowledge of using over the counter drugs, for eg. in school days when one got a viral infection during winter months and father gave you antipyretic in high fever. Father at that time knew that it's a common viral fever and will resolve on its own and there is no harm if given 1 or 2 tablets for the comfort of the child. If illness deteriorates, then he used to take the child to the hospital on suspicion. If you have knowledge about the condition, about the drug used and about proper dosing and intervals one may go, but if you are suspicious do look for a doctor.
    – Sikander
    Commented Jul 30, 2020 at 12:57

As you have already described, the hypothalamus regulate the set point at which the body temperature is maintained. This set point is elevated in fever, reflecting an infection, or resulting from tissue damage, inflammation, etc. These conditions all enhance formation of cytokines such as IL-1beta, IL-6, TNF-alfa, and interferons, which act as endogenous pyrogens; this first phase is mediated by ceramide release in neurons of the preoptic area in the anterior hypothalamus. The second phase is mediated by coordinate induction of COX-2 and formation of PGE2 which (by a cascade of reactions) will trigger the hypothalamus to elevate body temperature by promoting an increase in heat generation and decrease in heat loss.

NSAID's (Nonsteroidal Anti-Inflammatory Drug) supress this response by inhibiting COX-2 and thus as well as the synthesis of PGE2. This is the fundamental therapeutic effect of this class of drugs - inhibit prostaglandin (PG).

Now regarding your question specifically, NSAID's reduce fever in most situations, but not the circadian variation in temperature or the rise in response to exercise or increased ambient temperature. Normal body temperature in healthy humans is not affected by NSAID's because there are no PG's triggering the hypothalamus in normal conditions.

There is a danger however... and that is due to toxicological effects specially with paracetamol (acetaminophen) which may cause liver injury with unintentional overdose; and if the drug has too much affinity for COX-2 enzymes (some companies were very well sued for that)


Rang & Dale's Pharmacology

Sorry, I misread your whole question.. the question was if it is good or not to have fever, you can remove the upvote if you like.

I've found this article which concludes that

Early administration of acetaminophen to treat fever due to probable infection did not affect the number of ICU-free days

That is a true dilemma, in one hand it is relatively safe to not take any antipyretic medication for minor illnesses, and let the system defend itself, on the other as some studies reveal it does not affect or worsen the outcomes.

  • I was interpreting the question as, while healthy if we took paracetamol our temperature would decrease more and more.. again sorry for the confusion
    – program
    Commented Jul 28, 2020 at 13:44
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    +1 for your research. But yes, the question still remains unsolved, whether we should wait for the fever to automatically go normal, instead of taking antipyretics immediately. Commented Jul 28, 2020 at 15:38

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