This is a randomized, double blind, placebo controlled, parallel group, study in patients with chronic rhinosinusitis with or without nasal polyps. The objective is to test the clinical efficacy of long-term low dose oral doxycycline on wound healing quality after endoscopic sinus surgery.

Inclusion Criteria:

• at least 18 years of age, of either sex and any race
• diagnosis of chronic rhinosinusitis with or without nasal polyposis according to the EPOS guidelines research
• Subjects should be regularly scheduled for bilateral functional endonasal endoscopic sinus surgery
• Subjects must be in good health, free of any clinically significant disease that would interfere with the study schedule or procedures or compromise his/her safety.
• Subjects must be willing to give informed consent and adhere to visit schedules, medication restrictions, and agree to perform daily diary entries.
• Nonpregnant women of childbearing potential must use a medically acceptable, adequate form of birth control.

Exclusion Criteria:

• Women must not be pregnant, breast feeding, or premenarcheal.

• Subjects who have required oral corticosteroids within the previous four weeks prior to surgery.

• Subjects who have required nasal corticosteroids within the previous one week prior to surgery.

• Subjects with known allergic reaction on tetracyclines, diabetes (type 1 and 2), renal insufficiency, severe liver disease, systemic diseases affecting the nose (e.g. M. Wegener), prior surgeries of the paranasal sinuses.

• Patients with the following diseases should be excluded :

  1. Cystic fibrosis based on positive sweat test or DNA alleles
  2. Gross immunodeficiency (congenital or acquired)
  3. congenital mucociliary problems e.g. primary ciliary dyskinesia (PCD)
  4. Non-invasive fungal balls and invasive fungal disease
  5. systemic vasculitis and granulomatous diseases
  6. Cocaine abuse
  7. Neoplasia