Tc-99-m-latex particles (LP) is a newly developed radiopharmaceutical for the evaluation of the gastrointestinal (GI) tract. Following oral ingestion, it passes through the entire GI tract undissolved. The purpose of the present investigation was to introduce the clinical application of Tc-99-m-LP. A group of 11 healthy volunteers was studied. Following a 12 h fast, the subjects were given 150 ml of water containing 37 MBq of Tc-99-m-LP orally. Dynamic images up to 2 h were recorded to document temporal progression of radioactivity. Static images of the abdomen and whole body were taken at intervals. In normal subjects the tracer arrival times at the caecum and sigmoid colon were 3.2 +/- 0.9 and 11.2 +/- 3.2 h, respectively. The average t1/2 value for gastric emptying, 50% colonic filling and small bowel transit time were found to be 21.6 +/- 5.6, 233 +/- 72 and 211 +/- 66.4 min, respectively. In conclusion, Tc-99-m-LP has the potential of providing functional information of the GI tract.