This is a randomized controlled trial to explore the efficacy and safety of washed microbiota transplantation (WMT) for diabetic gastroparesis (DGP) patients.

At least 44 subjects who meet all the inclusion criteria but do not meet any exclusion criteria will be enrolled in this study. Data of demographic characteristics, Gastroparesis Cardinal Symptom Index (GCSI), Patient Assessment of Upper Gastrointestinal Symptom Severity Index (PAGI-SYM), Gastroparesis Core Symptom Daily Diary (GCS-DD), Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life (PAGI-QoL), and clinical outcomes will be collected. After treatment, they will enter the follow-up period for efficacy and safety evaluation.

Inclusion Criteria:

Subjects must meet all of the following inclusion criteria to enter the study:

1. Diagnosed with diabetes for over 1 year;
2. Accompanied by symptoms such as abdominal bloating, early satiety, persisting for at least 3 months, with a GCSI Total Score greater than/equal to 2.3;
3. Objective evidence of delayed gastric emptying within the past 3 months, including but not limited to scintigraphic gastric emptying or gastric ultrasound;
4. Upper gastrointestinal obstructive lesions were ruled out by imaging or endoscopic examination within the past 3 months;
5. Males and nonpregnant, non-breastfeeding females who are aged more than 18 years and sign the informed consent form;
6. The subject or his/her legal representative gives informed consent, fully understands the purpose of the study, is able to communicate effectively with the investigator, and comprehends and complies with the requirements set forth in the study.

Exclusion Criteria:

Subjects meeting any of the following exclusion criteria must be excluded from the study:

Subjects who:

1. Have any upper gastrointestinal pathology other than diabetic gastroparesis that would require therapy other than that provided in this trial;

2. Have a prior history of gastric surgery, including but not limited to gastric bypass, gastrectomy, gastric banding, pyloroplasty, fundoplication, or vagotomy in past 1 year;

3. Have any organic/neurological disease that is suspected to be causing gastroparesis, other than diabetes;

4. Have been using medications affecting gastrointestinal motility, such as GLP-1 agonists;

5. Have contraindications for intestinal tubing;

6. Have a history of medication that regulate intestinal microbiome in last 48 hours;

7. Have serious diabetic complications need immediately be dealt, such as diabetic ketoacidosis

8. Have poor lung function and those deemed by the investigator to be affected by the study treatment, such as during COPD exacerbations;

9. Have any of the following abnormalities in cardiac function and cardiac performance:

   • Cardiac function rating≥Ⅲ according to New York Heart Association (NYHA);
   • New myocardial infarction or unstable angina pectoris within 6 months;
   • Electrocardiogram indicated prolonged QTc interval (male QTc≥450ms, female QTc≥470ms);
   • requiring drug intervention (more than Ⅱ atrioventricular block).

10. Have preexisting hepatic disease that meets Child-Pugh Class B (moderate; total score 7 to 9 points) or C (severe; total score 10 to 15 points);

11. Kidney disease with KDIGO stage 3b (GFR<45 ml/min/1.73m2) or above;

12. Have infectious diseases such as active hepatitis (requiring long-term use of drugs), HIV or active tuberculosis;

13. Have a history of drug abuse, alcoholism (defined as consuming more than 14 units per week, with 1 unit equivalent to 360 mL of beer, 45 mL of 40% alcohol, or 150 mL of wine), or substance misuse;

14. Other significant systemic illnesses, such as malignant tumors;

15. Have other situations in which the investigator deems it inappropriate to participate in this study.