What Do you think Makes your eyes red?

Hey, Everyone im currently arguing with a friend about this. This is a little story about the whole thing....

After I just end my smoke sesh, I go into the bathroom to see if my eyes where red and they werent. So i come onto the computer lookin I came onto my computer and my friend started aiming me so i asked him if the bud I gave him made his eyes red. Then he started going off about, how the smoke makes your eyes red. Not the Bud and the smoke makes your eyes dry. I told him hes in idiot because when you smoke. Your eyes turn red and glossy, not dry then red and dry either.

So I wanted to know what is it in marijuana that would make your eyes red? If there is a chemical then is it possible to produce plants with and with out it?

Sorry if this was bad I just wanted to know...

PEace

This has been asked and answered about 8 billion times here. THC causes vasodilation which makes your eyes red. Eye drops clear your eyes by vasoconstriction, which is just the opposite. We have a search feature which works quite well.

i've always considered it dryness. like your mouth sometimes gets, and like my voice and sinus sometimes gets as well.
I'm not sure though. you could have searched for this answer though. im almost positive it's somewhere on here.

Also, anyone can prove this simply by eating brownies or firecrackers; when you eat, your eyes still get red and your mouth still gets dry, but you haven't smoked anything.

My eyes always get red whenever I toke up. For some reason they DON'T get red when I smoke kush.