Q. Mother had pneumonia. She's fine now, but the hospital doctor didn't treat her 102-degree fever, saying it may help the immune system fight infection. Is this true?

A. Yes — unless there's another reason to use acetaminophen (Tylenol), like underlying heart disease or bothersome pain, Mandell's "Principles of Infectious Diseases 2005" lists reasons why fever may actually be good for you.

Many studies show increased resistance to infection with higher fevers. For example, one study (by Kluger and associates) infected iguanas with a germ called Aeromonas and found that higher fevers improved survival rates, while reducing fever with drugs worsened survival. A Dr. Richard Bryant and his research team found that the higher the fever in humans with blood infections, the better their survival.

The core temperature of humans and animals increases in response to germs and viruses. But since fever requires extra nutrients and is a metabolic burden, it is unlikely that we would have developed such a response unless it helped fight infection.

In 1989, Dr. T.F. Dorn and others from Johns Hopkins University found that treating chicken pox with Tylenol actually prolonged illness. In another study, Dr. Neil Graham and others found that aspirin and Tylenol worsened cold symptoms and reduced antibody levels. And in 2005, Dr. Carl Schulman and others from the University of Miami studied 82 injured patients without head trauma in their trauma intensive care unit. The patients were randomly divided into two groups. One group was started on Tylenol early — when fever reached 101.3 degrees, adding a cooling blanket at 103. The other group was started on Tylenol and cooling blankets at 104 degrees. There were fewer deaths in the group whose fever was allowed to reach 104. Thus, aggressively treating fever in the critically ill may actually cause more deaths.

So there's little evidence that fever per se is harmful. Harrison's "Principles of Internal Medicine" confirms that the routine use of Tylenol "given automatically as 'standing,' 'routine,' or 'prn' orders to treat low-grade fevers in adult patients on hospital wards is entirely unacceptable."

And in keiki with fevers, using Tylenol does not help prevent febrile seizures. In the pre-antibiotic era, fever therapy was even used to treat various diseases, pushing fevers as high as 107 degrees with little consequence. Tylenol also reduces muscle aches, further fooling us into thinking that it also helps fight infection.

Avoid making people with infections miserable by taking off blankets or applying ice packs. Per Mandell, shivering may cause spasm or narrowing of diseased heart vessels while also causing an increased metabolic burden (oxygen demand). Maybe nature wanted your mom to have a fever of 102 for good reasons.

Dr. Landis Lum is a family-practice physician for Kaiser Permanente and an associate clinical professor at the University of Hawai'i's John A. Burns School of Medicine. Send your questions to Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; fax 535-8170; or write islandlife@honoluluadver tiser.com. This column is not intended to provide medical advice.