" Some of my patients suffer greatly after a single course of antibiotics, even if the antibiotics were absolutely necessary. This is exactly what happened with Greg. He consulted me about symptoms that were not clear at all. Greg had frequent episodes of cold-like symptoms, which had been occurring regularly for over two years. The strange part was he never presented a fever or cough. He also suffered through bouts of depression, which affected him even though everything in his life was working well. When I asked Greg about his health history, he told me that he had had pneumonia two years earlier. Doctors—rightly—had prescribed a round of levaquin, a very strong antibiotic. "

― Alejandro Junger , Clean Gut: The Breakthrough Plan for Eliminating the Root Cause of Disease and Revolutionizing Your Health