This study looks at how a treatment called Fecal Microbiota Transplantation (FMT) can help people with a condition called Irritable Bowel Syndrome (IBS). IBS causes stomach pain and changes in bathroom habits. FMT involves taking healthy bacteria from one person's poop and putting it into another person's gut to help balance their gut bacteria. This study will test if FMT helps IBS symptoms better than a fake treatment called a placebo.

Participants will be split into three groups. One group gets placebo capsules and placebo enema. The second group gets placebo capsules and FMT enema. The third group gets FMT capsules and placebo enema. This study will help find out if FMT is better than placebo and compare two ways of giving FMT.

• The study is for adults 18-70 years with IBS and lasts several months.
• Participation involves taking capsules and/or receiving enemas.
• People who are pregnant or have other serious health issues cannot join.