Jet

Jet is a powerful methamphetamine that stimulates the central nervous system. The initial euphoric rush rarely lasts more than a few minutes, but during that time, the user is filled with a rush of energy and strength. The drug was synthesized by Myron, and is extracted from Brahmin dung. Jet seems to be taken from an inhaler.

History
When Myron first encountered the Mordinos, they were farming peyote cacti and trying to sell it to tourists as the “Reno Experience”. Unfortunately peyote trips are too long, and profit is generated by fast turn around and a high addiction rate. Furthermore the climate was far too ravaged and irradiated to grow most vegetable matter but the hardiest of plants, so Myron began delving in growing shrooms. Hallucinogens have low overhead and thrive in plentiful brahmin dung. From there Myron began experimenting with derivatives of lysergic acid diethylamide and psilocybin and THC the active substance in marijuana(unknown to stil grow). However the Mordinos still desired something a little harder and more addictive that could get them Redding. The solution to the problem came from the Brahmin fertilizer itself.

In the prewar days, big meat companies had experimented with a cheap protein extract for growing food. However, the product had to be abandoned because infection of even a skin bacteria resulted in a complex technical relation causing it to act like a methamphetamine. To cut their losses farmers fed the extract to their cattle. A protein extract was obtained and then corrupted. By placing the augmented Brahmin dung in large vats they could gather the potent drug they were searching for. About a hundred slaves were killed in initial testing, mostly results of heart attacks, cerebral hemorrhages, and psychotic episodes. Myron now spends his time refining jet and making it more addictive. Thanks to Myron and the Jet, the Mordino family built their drug empire.

Its creator, Myron would die less than a year after the Chosen One defeated the Enclave, stabbed to death by a Jet addict in a bar at the Den. While no one remembers that Myron created Jet or even remembers his name, his creation would live on, apparently even somehow spreading to the Capital Wasteland, where someone would produce an even more potent version.

Jet is highly addictive; more so than any other other chems and drugs. Dr. Troy therefore has created a Jet Antidote for Dr. Johnson and the People of Redding where a high percentage rate is addicted.

Fallout 3
Jet returns in Fallout 3. It is cheaper than in Fallout 2, but the effects are lessened, too. In Fallout 3, it provides +30 Action Points.

There is a more potent variant of Jet called "Ultra Jet", but it still does not seem to be as potent or addictive as the Jet encountered in Fallout 2. The newer, more powerful drug was developed as an attempt to market Jet to ghouls, who were almost unaffected to the effects of common jet.

Inconsistencies
While it is said that Myron created Jet, Mrs. Bishop says that she got hooked on Jet by Bishop (before they got married) and for that she got kicked out of Vault City, which would require Jet to be much older than Myron is. According to Chris Avellone, what Mrs. Bishop says is a mistake and is not canon. It is more likely that Bishop got her hooked on some other drug. Consistent use of Jet will have muddled Mrs. Bishop's perceptions in any case.

In Fallout 3, Jet can be found in containers located in a sealed Vault, implying a pre-2077 origin, but this appears to be an unintentional product of randomized loot tables. Or it could be that when the vault was open (before the PC is born) that Jet got inside the vault.

Trivia

 * A drug called Khat (pronounced jat) enjoys popular use in Africa as a stimulant. The leaves can be chewed like tobacco or brewed like tea, and imparts feelings of euphoria and alertness that can verge on mania and hyperactivity depending on the freshness and quality of the leaf. (Source: Los Angeles Times)

(source: wikipedia )
 * Another "drug" called "Jenkem" (pronounced Jenk-em) also popular in affrica is made by fermenting dung and urine of any creature (offten cow dung) for several days and then huffing the accumulated methane gas. It supposedly produces an out of body experience along hallucinations and euphoria.