Drugs

In the broadest sense, drugs are substances other than foods that are consumed in some fashion for the purpose of causing physiological changes in the body. Pharmaceutical drugs or medicines are those substances that are intended to diagnose, treat, cure, or prevent disease. Various intelligent species and civilizations of the Milky Way galaxy have developed and used drugs for millennia.

Sangheili
Doctors are rare among Sangheili due to the widespread aversion to surgery in the species' cultures. However, the stigma against the cutting of flesh outside of battle has not kept them from using medicinal substances. Sangheili have drugs that not only for healing, but also for memory improvement and for dealing with anxiety. It is common to find all of these varieties of medications in temples built for kaidons, which traditionally have been visited by them prior to planning a military campaign. In such hallowed places, all manner of compounds are dispersed throughout flowing water, which has led to the label, "healing water". Included among these are nootropics, which naturally would be very useful for kaidons making plans for war. Anti-anxiety medications in the water, interestingly, take the form of micro-biotic organisms that evidently can produce this effect in Sangheili. The species also has a penchant for alcoholic beverages, including those produced by humans; but draughts can be found on Sanghelios as well. In the previously-mentioned temples, these may be laced with specific herbs.

San'Shyuum
"The San'Shyuum have always excelled in the arts of intoxication."

- a compliment from the Confirmer.

Medicinal comforts are mainstays of San'Shyuum culture. The drugs that are known to be consumed by the species are almost all those which provide pleasure and are used recreationally. Remedial substances do exist, of course, and some of those things used for pleasure also have healing properties. In the time prior to the firing of the Halo Array, the alcoholic kasna made on Janjur Qom was even held in high regard by certain Forerunners. Thousands of years later, it is tea, not alcohol, that was prevalent among the San'Shyuum of the Covenant. These teas could be flavored with herbs such as sky spice and sea flower. One herbal tea in particular was used as a quick-acting analgesic for those with headaches, commonly brought on by the smoking of hookah tobacco. Hookah tobacco used by the Covenant's San'shyuum was smoked with the aid of a water pipe. Being a stimulant, individuals used it to grant themselves extra focus and mental acuity for a short duration. The aforementioned herbal tea that could be used to alleviate hookah-induced headaches, was produced with the aid of an herbal synthesizer, a device which could formulate any number of prescriptions. These synthesizers relied on Forerunner technology and were almost exclusively set aside for the use of privileged San'shyuum ascetic clerics. In the tower districts of High Charity, a large room known as the Chancel of Recovery was filled with the gas of vaporized herbal ointments that were beneficial for the skin and lung tissue of San'shyuum. These vapors had no narcotic properties; the chancel was a place of healing and meditation. Th herbs cultivated for the Chancel of Recovery were not meant for Sangheili biology, and it was taboo amongst San'Shyuum and Sangheili alike for a Sangheili to enter. Herbal steaming stations, similarly, existed apart from this large space.

The San'Shyuum of millennia past, like humans, were often owners of pheru. This meant that when a fine, desiccated powder consisting of inert, short-chain organic molecules was discovered aboard derelict ships of unknown origin and determined to have psychotropic properties when given to animals such as pheru, San'Shyuum gladly administered it to their pets. The effects made the pheru more docile, but the powder altered the genetic code of the creatures over time so that malformations appeared. Pheru began to eat one another and abortions were the norm among those that became pregnant. This led to widespread euthanasia administered by San'Shyuum caretakers.

Unggoy
"It's the gas, haha! When I'm on the gas, I don't know what I'm doing half the time!"

- An intoxicated Unggoy elatedly recognizes the source of his euphoria.

Unggoy are best known for being particularly fond of recreational drug use in general. Their portable methane tanks are often also filled with what they refer to as infusions, which are narcotics. These infusions can be consumed this way through the same breathing apparatus that they use to supply methane in inhospitable atmospheres. Unggoy have been known to make remarks about "the gas" as a psychoactive substance, which likely refers to the same mind-altering infusions which can be inhaled when in that dosage form. More often, however, Unggoy will simply imbibe the compounds through a tube, similarly to the nutritious paste that they receive through food nipples. The organic chemical compound, benzene, is also treated as a recreational drug by Unggoy. It is possible that the aforementioned infusions and gas may sometimes include benzene, if not always and exclusively. Benzene mostly exists as a liquid, but it evidently is typically used by Unggoy when in a gaseous form, as it has been called "lovely lung gold". Benzene is highly toxic to humans; inhalation of trace amounts or drinking it can cause cancer. For Unggoy, however, it seems at least relatively tolerable. It has even been labeled "a sacred aromatic", by Unggoy in the Covenant, which points to it having religious connotations.

While knowledge of drugs used by Unggoy predominantly concerns those used for euphoria and disinhibition, Unggoy are known to be reliant on many other medications for all aspects of their health as well. In the years following the wake of the Great Schism and the dissolution of the Covenant, poor living conditions on Balaho only got worse, since the major chain of supply evaporated almost overnight. This environment made the planet eager and willing to pledge loyalty to the Created when Cortana broadcast promises of health, prosperity, and repletion. Soon after, ships appeared in the skies, bringing not only food, but medicine and other much-needed things as well.