I also take ABab and it does cause bad herxes. My LLMD states that it can sometimes take a couple of weeks for 1 drop to really kick in. I take ABab twice a day and up a drop in the am for a week and then up another drop in the pm. I will continue to stay on the increased doses for 2 or 3 weeks and then up again. It will take me quite a long time to get to 15 drops twice daily. I am in a constant herx with maybe only 1 day every other week of feeling halfway decent. I, too, have a lot of mucus with constant coughing......drives me crazy. Hang in there. I am so glad this topic was mentioned.