₃-adrenoceptors (AR) are expressed by cholinergic myenteric neurons and ₃-AR agonists are effective in experimental models of diarrhea. Our aim was to explore the effects of a ₃-AR agonist, solabegron, on gastrointestinal (GI) transit, safety, bowel function, plasma somatostatin, and solabegron pharmacokinetics (PK) following single and multiple doses. In a single-center, double-blind, parallel-group trial, 36 healthy volunteers were randomized to oral solabegron (50 mg or 200 mg twice daily) or placebo. Transit was measured using a validated method (^99mTc-labeled egg meal and ¹¹¹In charcoal delivered to the colon via delayed-release capsule). Stool frequency, form, and ease of passage were measured on validated daily diary; plasma somatostatin by radioimmunoassay and plasma solabegron and its active metabolite by validated LC-MS/MS analysis followed by PK analysis using non-compartmental methods. There were no overall or dose-related effects of solabegron on gastric, small bowel or colonic transit, plasma somatostatin levels, stool frequency, form, or ease of passage in healthy volunteers. Solabegron and active metabolite exposures (AUC and Cmax) at both dose levels were consistent with PK at similar doses in previous Phase I studies. We concluded that seven days of the ₃-AR agonist, solabegron, 50 or 200 mg twice daily, did not significantly alter gastrointestinal or colonic transit or bowel function. In this study, medication was generally well tolerated with few adverse events reported and no clinically significant changes in vital signs observed. Further studies on clinical efficacy, visceral sensitivity and gastrointestinal transit are required in IBS patients.