Why? One could say that about any duration, right?
8 hours seems pretty ‘normal’ from the few times I’ve been ill like this though - would basically feel like ‘most of a day’ or ‘most of a night’.
More commonly though, the placebo effect is just natural progression of the disease, errors in data collection (such as patients trying to be helpful and confirming that vague symptoms have somewhat improved), or errors in data analysis (such as lab techs thinking they've seen something in the sample that they expected to see there).
The psychological effects may or may not apply to infants - that's a somewhat separate question. The other effects definitely do - it's perfectly plausible that a lab tech looking for an improvement in an infant's blood sample after treatment "finds" it.
So I do agree these other effects exist, but I don't think they exist under the classification of placebo effect. It's possible one of these is at play in this study.
There's a reason real medicine requires preregistered double blind trials. It's just far too easy to get causation wrong without using rigorous scientific methods.
That's a gross oversimplification. You could continue to vomit. You could also die. There are multiple types/causes for vomiting. Not all vomiting simply stops on it's own.
"It's good old mind-tricks of correlation vs causation."
I'd say this is more than just mind tricks. The study shows there's a strong correlation and evident effects, which suggests studies should be done on the cause.
"There's a reason real medicine requires preregistered double blind trials."
Or in this case a grandfathered status (it is a "real" medicine as it is approved for sale). I also think this is, again, only a half truth. Double blind studies tend to provide the strongest evidence, but they are not the only kind of study accepted for drug approval.
If there's a scientific study, that might show something better than the giant fail-fest of cultural medical knowledge. I don't know of any human society that hasn't at least historically had a bunch of ineffective medicine that was widely used. Even modern western society probably has some - such as this Emetrol perhaps or wrong results of drug trials. An extreme case is China where normal doctors in hospitals routinely prescribe herbal remedies alongside conventional medicine.
Did you look at the study linked in these comments? Or are you just going to go on and on about cultural medicine and mind tricks?