Zombrex is a drug from the Dead Rising franchise designed to temporarily stop the infection obtained from a zombie attack from spreading once administered. It is a main plot point in Dead Rising 2 and its prequel, Dead Rising 2: Case Zero, as Chuck Greene searches for it to help his daughter Katey, who has become infected after being bitten by her zombified mother.
Zombrex, being the only known cure for stopping the zombification process, is hard to find and incredibly expensive. The drug is delivered to the recipient's system via a syringe contained in a transparent tube, administered as a shot. It must be taken every twelve hours in order to stave off the infection, with failure to comply or overdosing resulting in death.
In Dead Rising 2 though, there seems to be an updated version of the drug, this time only requiring administration every twenty four hours. Capcom has set up a Teaser Tie-in Site for Zombrex at http://www.zombrex.com