The goal of this observational study is to measure and compare the presence of microplastics in children with inflammatory bowel disease (IBD) and children without IBD. The main questions it aims to answer are:

Are microplastics detectable in different biological samples from children? Are there differences in microplastic burden between children with and without IBD?

Researchers will collect biological samples including: intestinal tissue (from routine endoscopy), stool, urine, blood.

Raman spectroscopy will be used to detect and characterize microplastics in each sample type. Participants will not receive any medication or intervention as part of this study. All samples will be collected during standard clinical procedures.

Inclusion Criteria:

• Age <18 years
• Undergoing clinically indicated gastrointestinal endoscopy
• For IBD group: confirmed diagnosis of Crohn's disease or ulcerative colitis
• For control group: no current or past diagnosis of IBD

Exclusion Criteria:

• Age 18 years or older
• Lack of informed consent from legal guardian
• Lack of written assent from the participant if age ≥13 years

Pediatric patients undergoing endoscopy at a tertiary care academic hospital. The study includes children with confirmed inflammatory bowel disease and children undergoing endoscopy for other indications as controls.