Acetaminophen, which treats minor aches and pains and reduces fever, may not have an effect on the flu virus or its symptoms, according to a new study.

International guidelines, including those of the British Infection Society, recommend anti-fever drugs like acetaminophen (also known as paracetamol) as they may help and are unlikely to cause harm. But the authors of the new study found that four daily doses of the medicine did neither good nor harm.

But “compared to placebo, acetaminophen did not reduce fever, appeared to have no effect on influenza levels, and no difference in clinical symptoms of the flu,” researchers said.