Yet another study shows Tylenol doesn't work so well — this time for flu

If you have the flu, taking Tylenol isn't likely to help.

Researchers from New Zealand just published a randomized control trial involving 46 people with flu viruses. About half of the participants got 1,000 milligrams of acetaminophen (Tylenol) four times a day for five days. The other half got a placebo.

Turns out the acetaminophen group didn't fare any better than the placebo group. "Regular daily administration of the maximum recommended dose of [acetaminophen] for 5 days had no effect on viral shedding, temperature or clinical symptoms in participants with [confirmed] influenza infection," the authors wrote. So the world's most popular over-the-counter painkiller didn't reduce flu symptoms or temperature, or help patients get better faster compared with the group that took a sugar pill. The one bright spot? There were no harms detected in the Tylenol group.

The authors note that this is just one small study, so it's not enough to base medical decisions on. However, it's not the first time acetaminophen has performed poorly in medical trials. For fevers and flu symptoms, researchers often recommend acetaminophen for children younger than 3 months, since it's safer than ibuprofen (Advil) at that age. But in studies of children who are older as well as adults, ibuprofen often outperforms acetaminophen.

The same is true for pain. When I looked into how pain researchers view acetaminophen, they all said they wouldn't recommend it generally. To be more exact, one told me, "I can't imagine why anybody would take acetaminophen." (You can read the full post here.)

Now, there are cases when people can't take ibuprofen or other over-the-counter drugs because of stomach or blood pressure problems, for example, and acetaminophen may be the best alternative. So it's a good idea to talk to your doctor about your choice of over-the-counter flu drug and painkiller, especially if you're taking any one pill on a regular basis. The medicine you've always been taking might not be the most effective, or least harmful, choice.