The H1N1 virus has so far proven vulnerable to the antiviral drugs Tamiflu and Relenza, which is good news. A cornerstone of the government's pandemic preparations was the stockpiling of 50 million doses of those drugs over the past few years, enough to ensure that doctors would be able to respond sufficiently to new outbreaks. But that capacity could be compromised if people begin stockpiling antivirals for their own use. Already there are reports of pharmacies running short of Tamiflu, and many hospitals in the U.S. have begun restricting the power to prescribe antivirals to just a few doctors. Also, the misuse or overuse of Tamiflu or Relenza by patients can promote resistance in the flu virus — effectively removing the only bullets from our gun.