Inflammatory bowel diseases (IBD) are immune-mediated diseases with complex pathogenesis. IBD's course is heterogeneous, as is the response of patients to drugs, but physicians often take a “one size-fits-all” approach. Many patients do not respond to their first treatment, lose response, or suffer adverse events caused by medications. The need to manage patients individually, through precision medicine, is clear. Personalizing IBD treatment depends on determining which patients are at high risk of adverse complications, choosing the best therapy for each patient and optimizing treatment efficacy through tight and tailored monitoring. To change the natural course of disease, an individual's prognosis rather than their symptoms should guide therapy. This thesis outlines current knowledge of IBD pathogenesis and discusses the use of precision medicine to manage IBD patients, with the goal of improving the quality of clinical practice through targeted care.