The goal of this clinical trial is to learn if oral lyophilized fecal microbiota therapy (ORAL-LYO-FMT) helps treat diarrhea-predominant irritable bowel syndrome (IBS-D) and prevent the recurrence of Clostridioides difficile infection (rCDI). The main questions it aims to answer are:

• Does ORAL-LYO-FMT reduce IBS symptoms?
• Does it prevent rCDI after treatment?
• What side effects or safety concerns might occur? Researchers will compare ORAL-LYO-FMT to a placebo (a look-alike capsule with no active treatment) to see how well it works.

Participants will:

• Be randomly assigned to take ORAL-LYO-FMT or placebo for up to 7 weeks
• Take capsules three times per week (Monday, Wednesday, Friday)
• Complete health questionnaires and have follow-up visits by phone or in person for up to 6 months The trial also looks at changes in quality of life, mood, and new or ongoing medical conditions over time.

Inclusion Criteria:

• 19 years of age and older

• Able to provide informed consent

• Must have at least one of the 3 following conditions:

  1. Irritable bowel syndrome with diarrhea- predominant (IBS-D) as reported by patients of type 6 or 7 in Bristol stool chart and Rome IV diagnostic criteria:

     1. Recurrent abdominal pain/discomfort** at least 3 days/month in last 3 months associated with ≥2 of the following:
     2. Symptom improvement with defecation;
     3. Onset associated with change in stool frequency;
     4. Onset associated with change in stool formation (with this last criterion fulfilled for last 3 months with symptom onset > 6 months prior to diagnosis

  2. Primary or 1 episode recurrent Clostridioides difficile infection which is actively treated with CDI antibiotic (oral vancomycin, oral metronidazole or fidaxomicin) and clinically responding to treatment based on physician assessment at the time of recruitment.

  3. 2 or more episodes of recurrent Clostridioides difficile infection, which is actively treated with CDI antibiotic (oral vancomycin, oral metronidazole or fidaxomicin) and clinically responding to treatment based on physician assessment at the time of recruitment.

Exclusion Criteria:

1. Planned or actively taking other investigational product
2. Unable to tolerate FMT or take oral medications.
3. Requiring systemic antibiotic therapy at the time of FMT
4. Actively taking probiotics [Consumption of yogurt is permitted]
5. Severe allergy to any food and/or medications
6. Major open abdominal surgery within the past 60 days
7. Receipt of chemotherapy or radiation within 8 weeks of screening.
8. Active small bowel obstruction.
9. Those who are pregnant or plan to be pregnant within 3 months of the study. This will be determined on history alone at time of study entry and subsequent follow up.
10. Those who are breastfeeding or plan to breast feed during the trial
11. Not expected to survive beyond 30 days.
12. Any current or previous medical or psychosocial condition or behaviours which in the opinion of the investigator may pose risk to the recipients or the study team

Exclusion Criteria:

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