What species are treated at St. Mungo's?

Question

Who can be admitted to St Mungo's Hospital for Magical Maladies and Injuries? Does the hospital admit non-human creatures? Does the hospital even have healers who are qualified to treat house elves, veela or goblins? Do they treat muggles? Can a wizard, for example, bring in his muggle spouse and get medical help from healers?

Answer 1

Magically-caused injuries (in Muggles) are treated at St Mungo's. It seems to be very much unusual, at least according to Mr Weasley who's something of an expert in Muggles and would be expected to know such things.

‘Anyway,’ said Mr Weasley, in a raised voice, ‘this time Willy’s been caught selling biting doorknobs to Muggles and I don’t think he’ll be able to worm his way out of it because, according to this article, two Muggles have lost fingers and are now in St Mungo’s for emergency bone re-growth and memory modification. Just think of it, Muggles in St Mungo’s! I wonder which ward they’re in?’

_{^{Harry Potter and the Order of the Phoenix}}

and

‘We have the same concerns,’ Fudge interrupted. ‘The Brockdale bridge didn’t wear out. That wasn’t really a hurricane. Those murders were not the work of Muggles. And Herbert Chorley’s family would be safer without him. We are currently making arrangements to have him transferred to St Mungo’s Hospital for Magical Maladies and Injuries. The move should be effected tonight.’

_{^{Harry Potter and the Order of the Phoenix}}

As to whether the spouse of a witch/wizard would be allowed to be visit St Mungo's, the answer is almost certainly yes. The partner in a mixed marriage is certainly allowed to know about magic and visit Diagon Alley so you'd expect them to be allowed to be treated at St Mungo's, albeit with the caveat that mundane Muggle maladies (cancer, for example) are likely to be treatable by ordinary wizarding healers anyway, obviating the need for a visit to the specialists at St Mungo's.

I decided that, broadly speaking, wizards would have the power to correct or override 'mundane' nature, but not 'magical' nature. Therefore, a wizard could catch anything a Muggle might catch, but he could cure all of it; he would also comfortably survive a scorpion sting that might kill a Muggle, whereas he might die if bitten by a Venomous Tentacula. Similarly, bones broken in non-magical accidents such as falls or fist fights can be mended by magic, but the consequences of curses or backfiring magic could be serious, permanent or life-threatening.

_{^{Pottermore - Illness and Disability by J.K. Rowling}}

Answer 2

According to Pottermore, all sapient species may be treated at St. Mungo's, for magical injuries, even if the victim happens to be a muggle. However, it is also stated that ALL mundane maladies are curable by magical means, so the hospital is holding back on its true healing abilities to the muggles, but this is to be expected under the Statute of Secrecy. Furthermore, just because a sapient species (wizard for example) recieved an injury which was mundane in appearance, does not mean that Mungo's wouldn't treat it, as Pottermore states that a leg broken using magic requires magical treatment, and will not heal properly through mundane methods, even though it is only a broken bone. My point, is that St. Mungo's will treat more than just humans, however humans are the main clientele, since they are injured by magic most frequently, and they have a greater access to the St. Mungo's facility.