Depends on if it's bacterial pink eye or caused by a virus.
If it's viral, you just have to wait for it to run it's course.
If it's bacterial, it requires antibiotics.
Personally, I exclude for it but I know many of our area public schools do not.
Here is the info my state's health department gives us about it:
http://www.hennepin.us/-/media/henne...fact.pdf?la=en