I didn't learn this until about six months ago, but when you take antibiotics, or if your pet goes on antibiotics, it destroys all of the good bacteria in the intestinal tract along with the bad. The good bacteria is needed to maintain healthy bowels. Not having the good bacteria leaves the bowel open to attack by any bad bacteria and/or mold that is ingested. Over time, this can cause problems. If/when my Sabina ever needs antibiotics, I will also give her probiotics to replenish the good bacteria in the bowel. My town has a holistic pet food store that sells probiotics for cats. If yours doesn't, you can find some at NATREN.COM. I believe it comes in a syringe for easy administration. I also feed her a dry food which contains probiotics. You can't overdose on probiotics. The more the merrier.