CBD tincture is not known to produce adverse side effects.  Some individuals may experience dry mouth. But if you are taking a CBD tincture to feel better, a little dry mouth is a small price to pay to feel better.
CBD may produce one other “side effect” of note:
CAUTION! CBD can potentially interfere with your liver’s ability to process other medications. CBD isn’t meant to replace prescribed medication (like heart or blood-pressure medication).  Be sure to talk to your doctor before taking a CBD product.  A common recommendation you will want to confirm with your doctor or pharmacist, is to allow your body to metabolize any existing prescription medications for at least two-hours before consuming a CBD product.