High Fevers, Brain Damage and Febrile Seizures

Many parents fear that high fevers will cause brain damage. This will not occur unless the fever is over 107.6 degrees F for an extended period of time.

Dr. Greene’s perspective on high fevers…

Many parents fear that fevers will cause brain damage. Brain damage from a fever will not occur unless the fever is over 107.6 degrees F (42C) for an extended period of time. Many also fear that untreated fevers will keep going higher and higher, up to 107 degrees F or even more. Untreated fevers caused by infection will seldom go over 105 degrees unless the child is overdressed, or trapped in a hot place. The brain’s thermostat will stop the fever from climbing above 106 degrees F.

Some parents fear that fevers will cause seizures. For the great majority of children this is not the case. About 4% of children, though, will sometimes have seizures with fever. These febrile seizures are caused by rapid increase in temperature, not by the height of the temperature. Once a child already has a high fever, a febrile seizure is unlikely with the current illness. In any event, febrile seizures are over in moments with no lasting consequences. Treating fevers early in these children may prevent further febrile seizures.

Published on: June 19, 2001
About the Author
Photo of Alan Greene MD
Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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Recent Comments

I used to get fevers of 107. I can remember clearly they had to get the fever down. First I was in a cold bath, some ice added, and wrapped me with a wet sheet. It wasn’t that they were mean in any way, just urgently getting the fever down the best way. Later I was told it was because of my tonsils. Still not sure but they have never been an issue since. Thank goodness.

Thank You for your time.

Laurie Kennedy Bray


That is a high fever. So glad fevers aren’t an issue for you now.

Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.