What causes clear discharge?

Where is discharge?: You can get clear discharge from many places eg eyes, nose, vagina, etc. Allergies, infections, excitement, etc can all lead to this. You'll need to provide some more details. Or better yet, go see your family doc for an evaluation.

Vaginal? Normal.: If you're talking about a clear, odorless, vaginal discharge, that could simply be normal flow, especially in a woman who has had children. If it is creamy and you are mid-cycle, it could be ovulation time. If it is itchy, then worry about yeast. If it is malodorous and copious, then worry about bacteria. Otherwise, go on about your week. (if it's not vaginal, then ask again, please).