Colonic transit markersโradio-opaque rings, wireless motility capsules, and scintigraphic microspheresโquantify large-bowel motility to guide therapy for chronic constipation, IBS-C, and opioid-induced ileus. Against a backdrop of rising functional-GI disorders, the Colonic Transit Marker market size is valued at US$ 84 million in 2025 and is projected to reach US$ 142 million by 2033, registering a CAGR of 6.8% as clinicians shift toward objective, reimbursement-friendly diagnostics. The growth outlook is anchored by expanding indications into pediatric motility assessment, the market forecast of broadening payor coverage for outpatient motility labs, and industry expansion propelled by single-use, bio-degradable marker sets that cut contamination risk and labor cost.