Combat Drug is taken by fighters (usually military personnel) prior to combat.  This drug considerably increases personal strength and endurance. The effect generally begins within a few minutes after ingestion, and generally lasts for several hours. Results may vary. When the effect wears off, the user typically experiences fatigue and some level of metabolic damage. 
Combat drugs appear as early as the TL–7 in modern form. They might appear earlier in certain civilizations with much higher levels of herbology or a more diverse selection of flora.
- Marc Miller. Starships (Game Designers Workshop, 1977), 44.
- Marc Miller. Imperial Encyclopedia (Game Designers Workshop, 1987), 67.
- Frank Chadwick, Dave Nilsen. Traveller: The New Era (Game Designers Workshop, 1993), 335.
- Marc Miller. Marc Miller's Traveller (Imperium Games, 1996), 70.
- Martin Dougherty. Guns, Gadgets and Gear (Avenger Enterprises, 2007), 59.
- Matthew Sprange. Core Rule Book (Mongoose Publishing, 2016), 109.
- Matthew Sprange. Central Supply Catalogue (Mongoose Publishing, 2016), 83.