For many years I had recurring sinusitus and was given Amoxacillin or Zithromax at least twice a year. I got a Candida infection something fierce and it took years to figure out it was Candida. Odd thing is, after taking anti-candida herbs, quad action digestive enzymes and watching my diet the Candida was cleared and my sinusitus disappeared as well. I know it sounds weird. Maybe I had somewhat of a Candida condition before the first bout of sinusitus and then the many courses of Antibiotics made it progressively worse? Maybe the Candida was causing the sinusitus?