Efficacy of Repeated Transcranial Magnetic Stimulation Combined With a Live Probiotic Tablet (Combined Bifidobacterium, Lactobacillus, Enterococcus and Bacillus Cereus Tablets, Live) in Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D)

Inclusion Criteria: 1. Must meet the diagnostic criteria for Irritable Bowel Syndrome of Rome IV. 2. Age range between 18-70 years. 3. The duration of the disease is more than 6 months. 4. There are no pathologic abnormalities or biochemical changes that could explain the bowel-related symptoms. 5. The IBS symptom severity score at baseline must not be less than 75. 6. No pharmacological treatment (excluding emergency treatment) for IBS for at least 2 weeks prior to the start of treatment; no concurrent participation in other clinical programs. 7. Voluntarily sign the relevant informed consent form and voluntarily participate in this clinical project. Exclusion Criteria: 1. Be less than 18 years old or more than 70 years old. 2. Those who suffer from severe liver, kidney, hematopoietic system diseases, cardiovascular and cerebrovascular diseases, and psychiatric diseases that significantly affect cognitive function. 3. Patients with clear organic diseases of the intestinal tract; patients with diabetes, hyperthyroidism and other systemic diseases that affect the digestive tract dynamics; patients who have had a history of surgery on the anus and intestines or the abdomen. 4. The presence of the following conditions affecting the efficacy or safety judgment: ① regular use of preparations and drugs affecting gastrointestinal dynamics or function; ② treatment with other treatments and drugs that may affect the results of the judgment. 5. Those who are pregnant, breastfeeding or less than 12 months after delivery. 6. Patients with severe fear of needles, metal allergies or sensitivities, or those with pacemakers. 7. Patients who do not comply with the randomized assignment to the treatment group or have a tendency to be unstable such as poor compliance. 8. Patients who are participating in other research projects. 9. Those who do not want to sign the informed consent form.