Cochrane author Rokuro Hama reviews the evidence of harms on neuraminidase inhibitors with a special focus on the two earliest registered molecules (Zanamivir, Relenza, Glaxo SmithKline and Oseltamivir, Tamiflu Roche). Hama provides what is probably the most extensive review of the evidence of neuaraminidase inhibitor harms ever undertaken. Hama’s evidence comes from a powerful mix of mostly hitherto untapped sources, including regulatory papers, clinical study reports, animal studies and published evidence. The evidence fails to support the mechanism of action mediated through antiviral action put forward by the manufacturers. A linked commentary by Tom Jefferson explains the significance.