Stimpack

"These inbuilt chemical delivery systems dose marines with a powerful mix of synthetic adrenaline, endorphins, and a psychotropic aggression enhancer. Marines on stims benefit from greatly increased speed and reflexes, but are subject to long-term side effects including and not limited to insomnia, weight loss, mania/hypomania, seizures, paranoiac hallucinations, internal hemorrhaging, and cerebral deterioration. Nonetheless, both commanders and the marines themselves stand by the use of stims as essential to their continued survival and effectiveness on the battlefield."

- The uses and risks of stimpacks.

The stimpack is an in-field chemical delivery system filled with a variety of stimulants. These devices are featured as part of the CMC-200, CMC-400, and later-model CMC-660 combat suits. They are widely used by terran infantry.

Although the stimpack is built into these armors, smaller, portable stimpacks exist. These stimpacks can be applied directly to the neck and are compatible with CMC-200 combat suits.

StarCraft
Stimpacks will not activate if the unit has 10 or less hit points left. Activating stimpacks again before the previous use has worn out resets the timer and subtracts additional hit points; the unit's cool down does not decrease further.

Use medics to get the most from stimpacks.

Some hero and NPC units may come with a pre-researched stimpack ability. Its effects are the same as the researched ability.

StarCraft II
Stimpacks in StarCraft II can be used by s and marauders in multiplayer. Bunkered marines can use their stimpacks while fighting in the bunker. Unlike marines, marauders take 20 health damage per use of the stimpack instead of 10.

Use medivac dropships and/or medics to get the most from stimpacks.

Development
The upgrade used to take 170 seconds to research. It was researched at the merc compound. It also applied to reapers in multiplayer.

In the StarCraft II: Wings of Liberty single player campaign, Tychus Findlay was also intended to have been given a variant of the Stimpack ability named "Tychus' Secret Stash". It is described instead as a mix of rocket fuel, methamphetamine and various chemicals. Only the button remains in the map editor.