Dr. Russell O. Schub, FACP. As a highly rated gastroenterology practice in Columbia, MD, we specialize in the diagnosis and treatment of gastrointestinal illnesses. We proudly serve the Baltimore-Washington area for a variety of issues ranging from hemorrhoids to Crohn’s disease. Our methodologies and innovative techniques, including hemorrhoid banding and on-site infusion therapy with Remicade, continue to elevate the practice. We strive to be one of the most highly sought gastroenterology practices in Howard County.