Ebott City Sanitorium sits opposite the mountain it and the nearby city take their names from, on the outskirts of town. It isn't the most reputable place, in a time where many mental institutions have been shut down in the name of far more personal, reliable care, but strives to take the best care of its patients as can be rendered.
Frisk's admission to the sanitorium was on a need basis, seen as dire due to her rantings about monsters and magic, saying nothing of her decade long disappearance, but brought them a great deal of trouble following her forcible institution. Strange things occured around the desperate, insane woman, from windows shattering to pieces of furniture levitating, and it was with a great deal of, what they thought, caution and forethought that they administered chemical restraints to Frisk, to keep her docile and from harming herself and others in her "delusion".
The woman thought that she was married to a skeleton, for Christ's sake. She was out of her mind.
The revelation that she was pregnant with Aliza when given those drugs, despite tests having been done to prove otherwise ("No, doctor, we tested her! We have the paperwork! We followed all procedures, but there it is! She's definitely pregnant!"), was the last of many mistakes that the sanitorium committed. Frisk's mother, who had been searching for her daughter ever since a report had been put out in the local paper, found out where Frisk had been taken and threatened to sue the institution for their negligence, and was paid handsomely for her silence and taking Frisk into her care, a silence which she would eventually break when that money was gone, spent on her daughter's funeral and Aliza's upbringing.
The asylum did not survive the charges pressed on them with that suit. The building sits empty to this day, a hollow husk full of bad memories, abandoned medical equipment, and more than metaphorical ghosts.