I was perscribed this medication for a bacterial infection. I have only been on doxycycline for 3 days (1 dose of 100 mg in the AM and another in the PM) and each morning with or without food I am nausiated until late afternoon. I have also experienced a loss of appetite, headaches, acid reflux, and severe hot flashes. The doc says to keep taking as perscribed unless my side effects get much worse. I can't wait until I am normal again!