Objective To evaluate the efficacy and safety of prucalopride two mg once daily in the treatment of chronic constipation (CC) in China.Methods In this multicentre,randomised,placebo controlled,parallel-group,phase Ⅲ study,patients with CC received either two mg prucalopride or placebo,once daily,for 12 weeks.The primary efficacy endpoint was the proportion of patients reaching an average of three or more spontaneous complete bowel movements (SCBM) per week during the 12 week treatment.The key secondary efficacy endpoint was the percentage of patients reaching three or more SCBM/week during the first four weeks of treatment.Other efficacy assessments included the average number of SCBM/week; the median time to onset of first SCBM after intake of the first dose of trial medication and the average number of bisacodyl tablets or enemas used per week.Furthermore,the symptoms of constipation were assessed by patient assessment of constipation symptom (PAC-SYM) questionnaire.The quality of life was evaluated by patient assessment of constipation-quality of life (PAC-QOL) questionnaire.Safety assessments included adverse events,laboratory values and cardiovascular events.Results Four hundred and forty-six patients from China were screened,313 were treated and 295 completed 12-week study treatment.Averaged over 12 weeks,significantly higher proportion of patients on prucalopride two mg (39.4％,P＜0.01) had three or more SCBM/week compared with placebo (12.7％,x2 =29.50,P＜0.01).Over four weeks,significantly higher proportion of responders was also found in patients on prucalopride (40.0 ％vs 13.3 ％,x2 =28.58,P＜0.01).Prucalopride also significantly improved associated symptoms and quality of life (QOL).The most frequent treatment emergent adverse events were diarrhoea,nausea,abdominal pain,and headache,which were mild to moderate and transient,spontaneously resolved in a few days.Conclusion Prucalopride two mg once daily significantly improved bowel function,associated symptoms and satisfaction in CC over a 12-week treatment period,and was safe and well tolerated in Chinese patients.