Purpose: To investigate the safety and efficacy of an extract of Ziziphus jujuba for chronic constipation.Constipated patients received liquid Z. jujuba or placebo for 12 weeks. Subjects completed questionnaires, a visual analog scale and transit time (TT) tests before and after treatment. Results: Of 37 patients with a prolonged TT, 18 received the study drug and 19 a placebo. Two (12%) of the study and 16 (84%) of the control group dropped out due to severe constipation. The TT decreased from 12.2 particles for the study group to 3 particles at week 11. Symptom severity ratings decreased from 6 and 6.2 to 2 and 5, and the quality of life score improved from 1.9 and 2.3 to 1.3 and 1.4 in the study and control groups, respectively. Conclusion:Z. jujuba extract is an effective and safe treatment for chronic constipation.