 The Department of Otolaryngology at Mount Sinai is looking for adults with sinus disease with polyps, otherwise called chronic rhinosinusitis with nasal polyps CRSwNP. Patients may be eligible to enroll in a study offering a cutting-edge therapy to help reduce symptoms and avoid surgery. The treatment combines an antibiotic doxycycline with oral steroids. Oral steroids are the mainstay of medical management for patients with CRSwNP. However, recent studies have shown that doxycycline helps improve symptoms as well by reducing inflammation and killing common bacteria that can cause symptoms. This study is the first to evaluate this combination regimen. 