[Coda]

It doesn't have to be very small animals, because the problem isn't that it causes choking or suffocation. The problem is that it shreds the delicate alveoli of the lungs. That works on creatures of any size, including humans. The damage happens at a cellular level, even damaging the DNA, which causes cancer.

In the US, doctors are allowed to recommend any efficacious treatment. There's not a playbook or something that they're required to draw from; they just have to have evidence to suggest that the treatment has been shown to help people. (Some insurance companies might refuse to pay for some kinds of treatments, though.) They'll get in trouble for recommending treatments that AREN'T known to be effective, but that's a different matter. So while you're more or less right, it's not as strict as it sounds.