For what it's worth, I've had several base tryptamine purging experiences over the last few years and there has clearly been no relation to the intensity of the trip or the dosage used and no nausea involved in it. My hardest purge was on 50 mg of DiPT, which produced psychedelic effects of extremely mild intensity, almost nonexistent, aside from the auditory distortions which I personally do not think are functionally related or should count as that, and even those were only of modest intensity. My mildest was probably on 50 mg of MET smoked actually which was one of the most overwhelmingly intense experiences for me so far. I've also purged hard on the second but not first time taking 100 mg of MPT orally and the first but not second time taking 50 mg of MiPT orally. Like I said, there is also never any nausea build-up to them and most of the time, always when taken orally, they actually come before rather than during or after the psychedelic comeup, and they come out of nowhere; I will be minding my own business and simply feel instinctively out of the blue that I need to puke, and I'll go do it without any hesitation and then it's just done and never returns.
I'm not saying that the purging has to be healing and such, but I am saying that I don't think it's caused by either dosing too high or feeling nauseous. I personally strongly suspect that it is just a pharmacologically-induced vomiting response, relatively reliable and independent from the other psychedelic pharmacological effects. That being said, I also think it being a reliable pharmacological vomit actually increases the argument that it could be "healing" because of how, as Shadowmeister, it just feels good and refreshing to puke, which technically would mean in this theoretical case that it would be a reliable pharmacological mechanism for causing one to feel "good and refreshed" which basically does meet my definition of a healing substance. Nonetheless, pharmacologically forcing yourself to vomit all the time one would think couldn't really be that good for you and ultimately it does not surprise that people having frequent purge experiences could indeed have the kind of gut problems Foreigner has observed. Just because it can have good effects doesn't mean it can't have bad ones too, and vice-versa.
Shadowmeister, a study was recently published by a large number of authors including David Nutt and Robin Carhart-Harris titled
The hidden therapist: evidence for a central role of music in psychedelic therapy. Their aim was to determine the impact that "welcome" and "unwelcome" music had on the parameters of the psychedelic experience they had recently been measuring through many other studies. They ultimately concluded that "the nature of the music experience was significantly predictive of reductions in depression 1 week after psilocybin, whereas general drug intensity was not" and that "music plays a central therapeutic function in psychedelic therapy. " In other words, their psilocybin trips were not apparently the critical factor in determining therapeutic effect, but the fact that they listened to music they like while tripping. If someone pukes on a psychedelic and receives a therapeutic benefit from the psychological experience they have as a result of it, who's to say the puking wasn't actually the critical therapeutic factor?
Just my two cents on the matter.