In the Resident Evil game "Resident Evil 6" and the movie "Resident Evil Damnation", Chris and Leon have two vials on their chest rigs.
What's in them?
Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.Sign up to join this community
I'm fairly sure those are signal flares (or possibly glowsticks), rather than vials of any particular substance. Admittedly, this is based on having seen these "fanart" images by JhonyHebert.
I'm trying to find a better source, but I can't think what else they could be