A 5-thia-.omega.-substituted phenyl-prostaglandin E alcohol of the formula (I) ##STR1## (wherein, all the symbols are the same meanings as defined in the specification), a process for producing it and a pharmaceutical composition comprising it as an active ingredient. The compounds of the formula (I) may be converted into carboxylic acids in the living body which can bind on PGE.sub.2 receptors (especially, subtype EP.sub.4) strongly, so the compounds of the formula (I) are expected to be useful for prevention and/or treatment of immunological diseases, asthma, abnormal bone formation, neuronal cell death, lung failure, liver damage, acute hepatitis, nephritis, renal insufficiency, hypertension, myocardiac ischemia, systemic inflammatory response syndrome, sepsis, hemophagous syndrome, macrophage activation syndrome, Still's disease, Kawasaki disease, burn, systemic granulomatosis, ulcerative colitis, Crohn's disease, hypercytokinemia at dialysis, multiple organ failure, shock, sleeping disorder and blood platelet aggregation.