Maybe that's a sign that your friend has a serious stomach problem...?

When you get really drunk and start to hiccup, there's a good chance you're gonna throw up, and hiccups are spasms in your diaphragm, so, maybe, automatically throwing up from Herb can be prevented by practicing intake/outtake breaths before, actually, smoking.

And I had the same problem with alcohol, for a year (three years after I started drinking), and I drank my way through it, so, maybe you can puff your way out of the problem.