I began Chantix on Jan. 10th. I stopped smoking with no problem, no cravings...desires, crabiness, etc. At 6 weeks (Feb. 22 or so) I find myself running to doctor every week because of SEVERE!!!!!! sore throat, then the feeling of a something stuck in my throat the next week, now - mouth is sore (never had mono) - seems like the very inside of my lips feel 'burned'...they sting. Test for strep came back negative. And I haven't kissed anyone in the past 6 months. Going for endoscopy on Monday - doctor possibly thinks it might be acid reflux, but I've never ever had that either. I was 100% healthy, fine, wonderful before I started taking this and now - all heck has broken loose. I've spent more money on Doctors/medicine in the past month than I would have a month of smokes....and now may possibly have something that could be with me the rest of my life (acid reflux). But...I am curious about the mono....interesting.