Hospital

Hospitals were places of work in which employees (including doctors, nurses and administrative staff) sought to heal temporary residents, damaged organic life called "patients". These institutions varied greatly in character. Some were small and make-shift — as on battlefields during time of war. Others were imposing, solid buildings with long histories of general care. Not a few specialized in particular kinds of medical care, like mental health. Still others gave themselves over to medical research, in which those admitted were more "subject" than "patient".

Perhaps because of the Doctor's outlook on life — not to mention his very name — many of the more important events in his life took place in hospitals. It was not uncommon for his own regeneration, injury to his companion or the presence of alien menace to land him in a hospital. Similarly, the Torchwood 3 team — and, to a lesser extent, Sarah Jane Smith and Mr. Smith — monitored the pattern of hospital admissions for any sign of threat to Earth.

As regenerative patient
While the Doctor's TARDIS was the more usual location for regeneration, he sometimes found himself in a human hospital during or immediately after the event. His third incarnation was the first to recover in hospital. Weakened from Time Lord-enforced change, the Doctor was taken from just outside his TARDIS to the Ashbridge Cottage Hospital in Essex. There, under the care of Dr. Henderson, his binary vascular system and unusual brain activity were first documented by humans. (DW: Spearhead from Space). Later, when he had just regenerated into his fourth self, he spent time in the field hospital at UNIT Headquarters near London. There, Dr. Harry Sullivan again noted the presence of two hearts and ineffectually tried to get the Doctor to rest in bed. (DW: Robot) However, the regeneration in which a hospital played the most significant role was that resulting in the Doctor's eighth life. It is likely, in fact, that the surgical staff of Walker General Hospital in San Francisco, led by Dr. Grace Holloway actually killed the Seventh Doctor on the operating table. Dismissing X-rays which clearly showed the presence of two hearts, and misreading the Doctor's rapid pulse for symptoms of cardiac arrest, emergency room attendant, Dr. Salinger, called for emergency cardiac surgery. Dr. Holloway then ordered anasthesia and an invasive procedure which, though undoubtedly sound procedure for a human patient, proved fatal for that incarnation of the Doctor. His body was taken to the hospital's morgue, where he regenerated. Suffering post-regenerative trauma, the new Doctor imprinted on Dr. Holloway, the last person he saw as his former self, and the pair subsequently thwarted the plans of the Master to take over the Doctor's remaining lives. (DW: Doctor Who)

On three occasions, the newly regenerated Doctor has taken clothes from a hospital and continued to wear them after leaving. (, Doctor Who, The Eleventh Hour)

As non-regenerative patient
On occasion, the Doctor sought medical care outside the scope of a regenerative crisis. Consequent to an explosion in a quarry, the Doctor came under the care of an intern at an unknown English hospital for an injury to his forearm. After shrugging off his own injuries, he used Dr. Carter's pathology laboratory to determine that Sarah Jane's more serious injuries were due to a threat from a silicon-based entity known as Eldrad. (DW: The Hand of Fear). Later, in the year 5000, the Fourth Doctor sought the specialized help of Dr. Marius at the Bi-Al Foundation to rid himself of infection by The Swarm. The innovative procedure required the Doctor and Leela to shrink to microcopic size and be injected into his own body, in order to precisely target the threat to his blood stream. (DW: ''The Invisible Enemy)

The Doctor also once faked vague symptoms so he could be admitted to Royal Hope Hospital to better investigate H2O scoops he noticed on the hospital grounds. There, he was examined by medical student Martha Jones, who subsequently assisted the Doctor in returning the hospital to London, after it had been teleported to the Moon. (DW: Smith and Jones)

Opinions about hospitals
The Doctor sometimes expressed strong views about hospitals. In particular, the Eighth Doctor noted an aversion to hospitals, arising from his regeneration in Walker General Hospital in San Francisco. (EDA: Legacy of the Daleks, Kursaal) The Tenth Doctor confirmed this displeasure with hospitals, saying that "they give me the creeps". However, he had an affinity for their little gift shops, as they clearly indicated where the hospital exit was. (DW: New Earth, Smith and Jones, Silence in the Library)

Onboard the TARDIS
The Doctor's TARDIS had a medical bay of its own that was at least sufficient to healing minor injuries. It, or another medical treatment area onboard, may have been as big as an entire hospital ward. (Sanctuary)

As part of staff
A few of the Doctor's companions were employed by hospitals prior to their involvement with the Doctor. Dr. Grace Holloway was a cardiologist as Walker General Hospital. (DW: Doctor Who). Hex was an emergency room nurse at St. Gart's Hospital in London. (BFA: The Gathering). Martha Jones was a student doctor at Royal Hope Hospital in London prior to meeting the Doctor. (DW: Smith and Jones). Rory Williams worked as a nurse in Royal Leadworth Hospital, though he may have been working, or at least hoping, to have become a doctor there. 

Temporary members of staff
On occasion the Doctor's companions have either temporarily lent their skills to a hospital, or simply pretended to be a member of staff. For instance, Ace pretended to be a part of the human resources department of St Gart's when investigating a Cyber threat there. (🇧🇫). Later, she, Hex and the Doctor worked alongside Florence Nightingale in a field hospital during the Crimean War. (🇧🇫)

As patient
The Doctor's companions often found themselves in hospitals, medical bays or research facilities, though not always by their own choice.

When admitted as genuine patient or subject
Jamie McCrimmon was struck ill on the Moonbase, and forced to seek medical treatment in its sickbay. 

Following an unexpected explosion in a quarry, Sarah Jane Smith was buried under rock and came into contact with the hand of Eldrad. The Doctor had her immediately transferred to a hospital where she came under the treatment of an un-named intern. The Doctor, meanwhile, used the facilities of the hospital's pathology department, under the supervision of Dr. Carter, to discover more about the mystery of the hand Sarah had discovered. 

The Doctor had to admit both Izzy Sinclair and Destrii to specialized medical facilities. After swapping bodies with Destrii, Izzy was taken to the Argus, a marine research vessel, to seek out the medical advice of marine biologist, Dr. Alison Lavelle. Later, after the two companions had returned to their rightful bodies, the Doctor took an injured Destrii to Hippocrates Base, a space-based facility that cared for a wide variety of species. 

Adam Mitchell once underwent a surgical procedure to implant a microchip into his head on Floor 16 of Satellite 5. While there, he learned that the satellite had emergency facilities on other floors. 

According to a soldier the Doctor met in 1914, Jack Harkness spent time in a hospital after sustaining a gunshot wound to the head during combat in World War I. The Doctor failed to explore exactly why Jack would have faked the need for a hospital. (IDW: The Forgotten)

Jackie Tyler ended up in hospital when she was mugged by an assailant who was attempting to steal her winning ticket for a "holiday" which would have turned her into a combatant in an alien war. Her stint in hospital ironically saved her life, as the mugger ended up being killed in the war in which she would have otherwise unwittingly participated (NSA: Winner Takes All)

Treated against their will
Polly was once nearly given an operation in a medical facility in Atlantis which would have converted her into a Fish Person. (DW: The Underwater Menace)

Amy Pond, Mo Northover and Elliot Northover underwent medical examination at the hands of a Homo Reptilian doctor. The elder Northover was dissected, as Amy nearly was, but in such a way as to do him no long-term harm.