Etrasimod is a synthetic, non-biological, orally administered small molecule sphingosine-1-phosphate receptor (S1PR) modulator. Etrasimod was approved by the Food and Drug Administration in 2023 and by the European Medicine Agency in 2024, constituting a new therapeutic option for the treatment of moderately to severely active ulcerative colitis in patients 16 years of age and older in the European Union. Its efficacy and tolerability have been demonstrated in several clinical trials both as induction and maintenance treatment, as well as in long-term extension studies. This article reviews the pharmacodynamic characteristics of etrasimod, its main differences with biological drugs and other small molecules (janus kinases inhibitors), as well as its clinical efficacy including certain subpopulations such as patients with isolated ulcerative proctitis, and the impact on their quality of life.