Are teachers allowed to search my bag and take property from me?

[Get-a-Life]

Constitutional protections don't extend to your interations with a private business, and your school is a private business. Like the others have said, it is probably in your handbook what teachers and students can/cannot do. Unless they're asking you to strip down for a strip search, don't get too wound up about it. I imagine asking to look in your bag for illegal contraband, i.e. a phone, is going to pass muster.