General Info

Gastrointestinal Specialists of Long Island (GISLI) is a state-of-the-art gastroenterology practice providing comprehensive digestive and liver care to all adults throughout Long Island. With two convenient offices in Wantagh and Malverne, New York, Drs. Novak and Marwil provide patients with unparalleled preventive care, advanced diagnostics, and effective treatments.The gastroenterologists at GISLI offer patients more than 30 years of experience. Theyve created a premier endoscopy center that ensures patients receive comfortable, personalized care. The practice offers upper endoscopy, colonoscopy, and office-based capsule endoscopy to view the entire small bowel. Breath testing is also available to evaluate for small intestinal bacterial overgrowth, lactose intolerance, fructose intolerance, and sucrose intolerance.GISLI strives to offer a safe haven to patients who might otherwise feel uncomfortable or discouraged from seeking treatment for rectal bleeding, constipation, inflammatory bowel disease, and other digestive disorders. They take pride in providing patients with empathetic care. Each physician ensures their patients receive the one-on-one treatment they deserve.Call Gastrointestinal Specialists of Long Island today or go online to schedule an appointment with a gastroenterologist.