Metal Gear Solid 4 Question

Hey GB, so I started playing MGS4 on a whim today, and for some reason Snake is repeatedly vomiting. I had this same problem on my second playthrough, I couldnt beat  Laughing Octopus, because Snake would stop to vomit every 10 seconds. Its not as frequent, but he keeps vomiting.
My life, and psyche is high.
Right now im fighting the fight with the frogs immediately before you face off with screaming mantis.
Any way I can stop the vomiting?
Or can someone at least tell me the reason why I am vomiting?

" Hmmm, are you constantly rolling? That could be the problem. "

do you use the syringe alot?

yeah snake is prone to motion sickness
lay off the barrel

Stop rolling around in the barrel so much.

Give the old guy a break man ;P

Come to think about it, having known what went on in that barrel I’d probably be vomiting too…

Well.
I dont kill much.
But I always roll around.
and use the syringe more than I should.

Haha, that's awesome. Man, I loved this game.

i just did some research and it looks like the syringe will cause vomiting after 10 uses

" @Icil: Thanks for your input. :P "