Background and aims: We examined the hypothesis of an antiinflammatory effect of phosphatidylcholine in ulcerative colitis. Methods: A phase HA, double blind, randomised, placebo controlled study was performed in 60 patients with chronic active, non steroid dependent, ulcerative colitis, with a clinical activity index (CAI) of ≥4. Retarded release phosphatidylcholine rich phospholipids and placebo were administered at a dose of 6 g daily over three months. The primary end point was a change in CAI towards clinical remission (CAI ≤3) or CAI improvement by ≥50%. Secondary end points included ≥50%changes in endoscopic activity index (EAI), histology, and quality of life scores. Results: Induction of clinical remission (CAI ≤3) as the primary outcome variable was attained by 16 (53%) patients in the phosphatidylcholine treated group compared with three (10%) in the placebo group (p < 0.00001). The rate of clinical remission and CAI improvement was 90%in the phosphatidylcholine group and only 10%in the placebo group. A median drop of seven points in the CAI score (70%improvement) was recorded in the phosphatidylcholine group compared with no change in the placebo group. Secondary end point analysis revealed concomitant drops in EAI and histology scores (p = 0.00016 and p = 0.0067 compared with placebo, respectively) . Improvement in quality of life was reported by 16 of 29 evaluated patients in the phosphatidylcholine group compared with two of 30 in the placebo group (p = 0.00005). Conclusion: Retarded release oral phosphatidy-lcholine is effective in alleviating inflammatory activity caused by ulcerative colitis. Background and aims: We examined the hypothesis of an antiinflammatory effect of phosphatidylcholine in ulcerative colitis. Methods: A phase HA, double blind, randomized, placebo controlled study was performed in 60 patients with chronic active, non steroid dependent, ulcerative colitis, with a The primary end point was a change in CAI towards clinical remission (CAI ≤ 3) or CAI improvement Secondary end points included ≥50% changes in endoscopic activity index (EAI), histology, and quality of life scores. Results: Induction of clinical remission (CAI ≤ 3) as the primary outcome variable was attained by 16 ( 53%) patients in the phosphatidylcholine treated group compared with three (10%) in the placebo group (p <0.00001). The rate of clinical remission and CAI improvement was 90% in the phosphatidylcholine gr oup and only 10% in the placebo group. A median drop of seven points in the CAI score (70% improvement) was recorded in the phosphatidylcholine group compared with no change in the placebo group. Secondary end point analysis revealed concomitant drops in EAI and histology scores (p = 0.00016 and p = 0.0067 compared with placebo, respectively). Improvement in quality of life was reported by 16 of 29 evaluated patients in the phosphatidylcholine group compared with two of 30 in the placebo group (p = 0.00005). Conclusion : Retarded release oral phosphatidy-lcholine is effective in alleviating inflammatory activity caused by ulcerative colitis.