Is it possible that antibiotics can lead to a gain in weight? I have just taken a course of antibiotics and have also taken canesten for the thrush that the antibiotics gave me. Could this have led to weight gain (3lbs)? Admittedly I have been travelling and it's possible the gain is from that, but I'm curious. I have kept away from ALL meds during my weight loss journey, even pain killers, and wondered whether there might be a correlation.