The aim of this multi-centered study is to understand the epidemiology of infectious complications after gastrointestinal surgery in China. In total, 17 centers from China will prospectively register their patients undergo gastric or colorectal surgeries. Patient demographic data, operation information, and postoperative data including the infectious complications and the outcomes will be registered. We expect to include 2000 gastric and 2000 colorectal patients within one year and the study is expected to be finished in 2020.

All participating hospital will log in on a website based e-CRF system. Researchers need to register the patient information that three time-points: admission, after surgery, after discharge.

The detailed registered information includes:

I. Basic and surgical information:

Age, height, weight, history of abdominal surgery, ASA score, surgical procedure, extent of lymph node dissection, extent of resection, time of surgery, amount of bleeding, whether it is emergency surgery, whether it is combined with organ resection, whether it is palliative resection, whether combined with preoperative treatment, whether combined with preoperative infection and intraoperative complications.

II. Postoperative information:

Primary lesion histological type, margin, pathological stage (pTNM); other complications, postoperative death and discharge time, CRP, PCT, WBC levels.

III. Abdominal Infection information:

Abdominal infection (Y/N), anastomotic leakage (Y/N), intervention, outcome.

Inclusion Criteria:

• Planned gastrointestinal surgery.
• Inform consent received.

Exclusion Criteria:

• Endoscopic surgery.
• Inform consent denied.

All adult patients undergo gastrointestinal (GI) surgery for GI tumor.