This cinnamon flavored chewing gum packs 100mg of caffeine in each piece. First Alert Gum is found in First Strike Rations and has been issued NSN 8925-01-530-1219. Granted, they taste slightly bitter but the cinnamon masks most of it. Within a minute you can feel the active ingredient kicking in. The website cites several studies confirming the advantages of caffeine for sustained combat operations and I can speak from personal experience that when your eyelids get droopy, this stuff works.
Sold by MMI Federal Marketing Corp, Stay Alert Gum is available at AAFES or on the web from www.stayalertgum.com.