"Loyalty bought at such a price is no loyalty at all."
Ketracel-white (or simply white) was an addictive narcotic containing an isogenic enzyme and nutrients. One of the active ingredients of white was yridium bicantizine. The Jem'Hadar soldiers of the Dominion were genetically engineered to lack the enzyme which white provided, and required frequent doses of the drug to survive. The white also provided all the nutrients they required, alleviating them of the need to eat or drink.
Without white, Jem'Hadar soldiers suffered withdrawal symptoms including pain, anxiety, loss of mental control, and inability to "shroud"; eventually, the Jem'Hadar spiraled into homicidal insanity. First killing their enemies followed by their allies, they inevitably turned on each other. Ultimately, their entire genetic structure collapsed. (DS9: "Rocks and Shoals") On rare occasions, a Jem'Hadar was born with a genetic mutation which allowed their bodies to produce the white they needed, though most such instances went unnoticed, as the Jem'Hadar with this mutation still took the drug on a regular basis and were unaware that they had no need to. (DS9: "Hippocratic Oath") All known attempts to remove this genetically engineered addiction failed, with the drug itself proving difficult to analyse and replicate by Starfleet methods (DS9: "The Abandoned").
The addiction to white ensured the Jem'Hadars' loyalty to the Founders. However, for most Jem'Hadar, this was unnecessary, as their loyalty was already absolute. Distribution of the white was controlled by the Vorta, and was dispensed to the Jem'Hadar First in a formal ceremony:
- Vorta: "First [name], can you vouch for the loyalty of your men?"
- Jem'Hadar: "We pledge our loyalty to the Founders, from now until death."
- Vorta: "Then receive this reward from the Founders, may it keep you strong."
Jem'Hadar bred in the Alpha Quadrant occasionally dispensed with the formal ceremony, claiming that their loyalty was shown by their actions rather than their words. (DS9: "One Little Ship") In the event of the death of the Vorta or the detachment of a group of Jem'Hadar from their main unit, the Jem'Hadar First could unlock the white case. (DS9: "Rocks and Shoals", "One Little Ship", "To the Death")
Early in the Dominion War, the Dominion in the Alpha Quadrant suffered from a white shortage, because a minefield prevented supplies shipping from the Gamma Quadrant, and because it was not easy to set up new production lines. The Cardassians proposed to exterminate some or all Jem'Hadar by poisoning the last white supplies. Later, the Son'a used their facilities on Devos II to produce large quantities of ketracel-white. (DS9: "Behind the Lines", "Statistical Probabilities", "Penumbra"; Star Trek: Insurrection)