Re: What causes your face to turn green sometimes?

Humans have always pushed fun to the limit to try to see just how far we 
can go. Well, some of us find our match with a simple rollercoaster. Many 
people lose their "cookies" or turn green from events like this which send 
our bodies into positions we weren't designed for.
     The turning green affect comes from the simple lack of blood in the 
skin. When our bodies are stressed out from things such as roller-coasters 
or dangerous encounters our hypothalamus triggers a "flight or fight" 
syndrome in our body. Adrenaline is pumped into our blood, the blood 
vessels shrink, blood is sent to our large muscles and heart and we 
sometimes even lose control of our bladders becuase our body is so worried 
and ready to fight off the problem. The part that interests you is the 
part that the heart and muscles needs all your blood. When this happens 
the red blood that was in your skin gets taken out for other more 
important organs. Our skin color is a dull yellow without blood and our 
veins show much easier. Veins are blue in color and so all we see is a 
very pale and blue face. What does blue and yellow look like when mixed? 
GREEN. 
     If this isn't the reason your friend turned "green"  than you might 
want to see if there is a spaceship nearby. Just kidding. 
     I hope this answers your problem. Keep up the interesting questions!