Phase I-II Clinical Trial - Safety and efficacy of umbilical-cord-derived mesenchymal stem cell (UC-MSC) in patients with active ulcerative colitis，randomized, single blind, controlled prospective study.

Phase I-II Clinical Trial - Safety and efficacy of umbilical-cord-derived mesenchymal stem cell (UC-MSC) in patients with active ulcerative colitis，randomized, single blind, controlled prospective study.

Thirty patients will be selected and randomized into two groups: the first group of 15 patients will receive a sole injection of UC-MSC and the remaining 15 patients will comprise the control group.

Every patient will maintain their standard treatment of active ulcerative colitis, with maximum tolerated dosage without side effects.

The day of infusion will be considered day zero. From that moment, followup will be divided into 0-1 week, 1 week-2 week,2 week-3 week, 3 week-1 month, and 3 month-6 months.

Clinical results will be analyzed after completion of 6 months of followup.

Inclusion Criteria:

• The diagnosis of active UC must have been confirmed by endoscopic and histological evidence.
• With mild and moderate disease.
• Men and women 18-65 years of age.
• Signed informed consent
• Capable of good communication with researchers and follow the entire test requirements

Exclusion Criteria:

• Patient with associated diseases such as diabetes mellitus, hypertension, dyslipidemia, atherosclerosis and malabsorption syndrome.
• With autoimmune diseases (lupus, HIV, cancer and hepatitis), colitis (infectious, post-radiation, post-drug, indeterminate) and Crohn's Disease.
• Abnormal hepatic or renal function
• Prior history of malignancy
• Pregnant or unwilling to practice contraceptive therapy or breast feeding females