In Westeros, the Order of Maesters is an organization of scholars, healers, and learned men. While not all maesters have, as a rule, received training in medicine (signified by a silver link in their chains), many have received medical training and serve as doctors throughout the Seven Kingdoms. Maesters appointed to major castles such as Winterfell or the Red Keep in King's Landing usually have been trained in medicine.
Woods witches are also commonly encountered throughout Westeros - local women with some basic skill in herblore that set up shop as apothecaries in the woods at the edge of villages.
- In the novels, the Graces who serve in the Temples of the Graces at major cities in Slaver's Bay are not only priestesses, but professional healers trained in the arts of medicine.
Known medical substances include:
- Essence of Nightshade - a sedative.
- Milk of the poppy - a commonly used painkiller, often administered to patients to render them unconscious so they can undergo major surgery (essentially like the real-life medicine morphine).
- Shade of the Evening - not strictly a "medical" drug, but a beverage drunk by the Warlocks of Qarth which they believe increases their magical powers (apparently with some mild hallucinogenic qualities).
Several lethal poisons are used by the world’s assassins. Though even strong medicines such as Essence of Nightshade are technically lethal if someone intentionally takes an overdose, poisons used in assassinations are more often subtle, and difficult to trace.
Diseases and medical conditions
Known diseases in the world include:
- The Great Spring Sickness - a devastating plague that tore through Westeros 90 years before the War of the Five Kings, which significantly reduced the population.
- Greyscale - a dreaded and usually fatal disease that can leave flesh stiff and dead, and the skin cracked and flaking, mottled black and grey, and stone-like to the touch. People suffering from very late stage greyscale infection are known as "Stone Men", and are exiled to colonies in ruined cities such as Old Valyria. Greyscale is known to occur in Westeros (including the lands beyond the Wall), but it is much more common in Essos, particularly the Free Cities.
Known physiological conditions, which are not "diseases", include:
- Dwarfism - a congenital condition in which a person is born with significantly below-average height, among this group is Tyrion Lannister.
- Dyslexia - Jaime Lannister has a dyslexia-like reading disability, according to both himself and his father, who recount that he had to spend many extra hours with his maesters to compensate for it and read at the same functional level as other people.
- Eunuchs - males who have had some or all of their genitals removed, often purposefully by slave-masters or as punishment for a crime, etc. (Varys, Theon Greyjoy, Grey Worm, etc.).
- Gout - Prince Doran Martell of Dorne has been suffering from severe gout for years, which has crippled his feet and left him wheelchair-bound.
- "Lackwit" - common term for the mentally disabled, covering a wide range of mental handicaps (Hodor, Orson Lannister, ect.)
- "Targaryen madness" - the noted tendency towards insanity that ran through the bloodline of House Targaryen, which resulted from many generations of compound inbreeding, incestuously marrying brother to sister to "keep the bloodline pure".
Behind the scenes
George R.R. Martin has stated that medical knowledge is officially more advanced in Westeros than in the real-life Middle Ages:
- "I made a deliberate decision when the books began to have the maesters, and have Westeros in general, have better medical knowledge than the real-life Middle Ages. Mostly because I didn't want everybody dying at twenty-six. So it is generally improved, the maesters have improved the standard of hygiene, and they understand certain practices, and they can do things better. Also, they have magic."
While this might seem incongruent with the otherwise static medieval level of technology in Westeros, much of real-life medical knowledge was discovered purely through trial and error (or even by accident, such as the discovery of antibiotics). The maesters might not know the underlying, theoretical reasons behind illnesses (what bacteria and viruses are), but they have accumulated a more advanced level of functional medical knowledge for practical purposes, such as what herb mixtures will heal infections, better surgical procedures, etc.
In the books
In the A Song of Ice and Fire novels, numerous other medicines, diseases, and medical conditions have been mentioned.
The real life disease dysentery is called "bloody flux" (also "pale mare") in the novels - apparently there are few treatments for it because it has been the bane of every army since the Dawn Age. Bloody flux devastates armies or slum districts it moves through, typically with a three out of four death rate.
The "grey plague" is a swift form of the Greyscale.
Another disease was the Winter Fever, a major plague that swept through Westeros in the bitter six year long winter that occurred in the aftermath of the Dance of the Dragons.
Naath, Missandei's home, is host to a horrific local plague known as "butterfly fever", because it is carried by the island's indigenous butterflies. Butterfly fever causes the infected to profusely sweat blood, and in the final stages makes flesh literally slough off the bone. The native Naathi people have a natural immunity to the disease - any outside force that attempted to conquer the island, even the Valyrians, would end up being killed off by the fever and none lasted on the isle for more than a year. Unfortunately, slavers eventually realized that the butterflies carrying the disease are only active during the day, so they were safe if they just made quick slaving raids at night which only lasted a few hours; subsequent waves of slaving raids devastated Naath.
It has never been mentioned in the novels that Jaime Lannister has a dyslexia-like reading disability.
Medical substances meant to induce abortion or prevent pregnancy are commonly produced across Westeros, particularly a drink known as "Moon tea" (made from a mixture of herbs, including tansy and pennyroyal). Moon tea can be produced upon request by castle maesters, as well as woods-witches. It is unclear what the attitudes are towards abortion by the major religions in Westeros: if they do not oppose abortion due to moral objections, or if they officially oppose abortion, but the rule is very commonly ignored and difficult to enforce in a decentralized medieval society.