Irritable bowel syndrome (IBS) is a chronic, recurring,and remitting functional disorder of the gastrointestinaltract characterized by abdominal pain, distention, andchanges in bowel habits. Although there are severaldrugs for IBS, effective and approved treatments forone or more of the symptoms for various IBS subtypesare needed. Improved understanding of pathophysiologicalmechanisms such as the role of impaired bileacid metabolism, neurohormonal regulation, immune, dysfunction, the epithelial barrier and the secretoryproperties of the gut has led to advancements in thetreatment of IBS. With regards to therapies for restoringintestinal permeability, multiple studies with prebioticsand probiotics are ongoing, even if to date their efficacyhas been limited. In parallel, much progress has beenmade in targeting low-grade inflammation, especiallythrough the introduction of drugs such as mesalazineand rifaximin, even if a better knowledge of themechanisms underlying the low-grade inflammation inIBS may allow the design of clinical trials that test theefficacy and safety of such drugs. This literature reviewaims to summarize the findings related to new andinvestigational therapeutic agents for IBS, most recentlydeveloped in preclinical as well as Phase 1 and Phase 2clinical studies.