Governments should review the use of the widely used anti-flu medication Tamiflu, scientists say after new research questioned the efficacy of the drug.
The study suggested that Tamiflu, which is used to prevent and treat influenza, shortens flu symptoms by between a day and half a day.
But the authors said there was "no good evidence" to support claims that it reduces flu-related hospital admissions or the complications of influenza.
The researchers, from The Cochrane Collaboration and the British Medical Journal (BMJ), also claimed that taking the drug could increase a person's risk of nausea and vomiting.
And when used as a preventative treatment it can stop people developing flu symptoms but may not prevent them from spreading flu to others, the authors said.
The findings of the review may cause further questions to be raised about the British and other government's stockpiling of the drug.
Britain's Department of Health began accumulating Tamiflu in 2006 in response to the increasing concerns about bird flu.
"The BMJ and Cochrane issue a joint call to government and health policy decision makers the world over, asking in light of the latest findings from the Cochrane Review, would you make the same recommendations today, choosing to stockpile Tamiflu?" a BMJ spokeswoman said.
Pharmaceutical company Roche said it "fundamentally disagrees" with the latest review.
And Britain's Department of Health said that Tamiflu has a "proven record" of safety, quality and efficacy. But a spokeswoman said that health officials regularly review all published data so will consider the latest Cochrane review "closely".
The researchers reviewed data from 20 clinical study reports on Tamiflu.
They found that taking Tamiflu led to an alleviation in flu-like symptoms an average of 16.7 hours quicker when compared to taking a placebo.
But they said that they did not observe any evidence in the reductions of hospital admissions or flu complications such as pneumonia or bronchitis.
But peers have criticised this finding, saying that most of the trials in the review were not very precise or reliable in how they defined and recorded the complications.
The researchers also found that taking Tamiflu increased the risk of nausea and vomiting by about 4 per cent in adults and 5 per cent in children.
Roche's UK medical director Dr Daniel Thurley said : "We disagree with the overall conclusions of this report. Roche stands behind the wealth of data for Tamiflu and the decisions of public health agencies worldwide, including the US and European Centres for Disease Control and Prevention and the World Health Organisation."
Commenting on the study Professor Wendy Barclay, influenza virology expert at Imperial College London, said most of the controversy surrounding the drug was about whether it should be stockpiled for pandemics..
"If another pandemic came tomorrow, and the government had no drug with which to treat thousands of influenza infected patients, I imagine there would be a public outcry."
