Dr. Cynthia M. Mullen is a gastroenterologist in Walnut Creek, California and is affiliated with John Muir Health-Walnut Creek Medical Center. She received her medical degree from Tulane University School of Medicine and has been in practice for more than 20 years. Dr. Cynthia M. Mullen has expertise in treating colonoscopy, upper gi endoscopy, inflammatory bowel disease (ibd), among other conditions - see all areas of expertise. Dr. Cynthia M. Mullen accepts Medicare, Aetna, Blue Cross - see other insurance plans accepted.