Not nausea as such. It's more a constricted feeling or tightness round the throat than it is a genuine feeling of wanting to puke. Not suggesting dose here, for information purposes only, but I typically aim for 80-100mg freebase, have stupidly gone higher at times ( never again! ) and only ever puked once. I was ( again stupidly ) drunk at the time. Make of that what you will! The feeling lasts around an hour or so, from strong onset to peak at around +2hrs, then disappears completely. GI discomfort the other end OTOH is rather more unpleasant and persists throughout the trip. I pre-dose with a coupla Loperamide to take care of that, no problem.