Small bowel capsule endoscopy (SBCE) has become an important tool in the evaluation of small bowel disorders. There is a major impact of SBCE on the clinical outcome in patients with suspected bleeding from the small bowel, in patients with chronic inflammatory bowel diseases, and with polyposis syndromes. The use of SBCE for patients with refractory celiac disease and for patients with unexplained symptoms such as chronic diarrhea and chronic abdominal pain is considered more and more frequent in clinical practice. This book chapter highlights the scientific background of impact on treatment decisions and outcome in patients with small bowel diseases by applying SBCE. A primary reason for the success of SBCE is the excellent diagnostic yield in detecting mucosal lesions when compared to radiology methods, including small bowel follow-through, small bowel enteroclysis, or cross-sectional imaging, such as CT scans or MRI. The high sensitivity of SBCE for mucosal lesions comes with a high negative predictive value of this method that impacts on clinical decision making in many instances. On the other side, SBCE is a non-invasive approach to the small bowel with solely diagnostic output. It, therefore, helps to diagnose small bowel diseases and is a complementary method to device-assisted enteroscopy, which permits the performance of therapeutic endoscopic interventions. SBCE and DAE should, therefore, be considered complementary procedures.