The effects of different nutrient meals and a noncaloric viscous cellulose meal (control) on the motor activity of the canine jejunum were studied. Contraction patterns were detected through six closely spaced, strain-gauge transducers and were analyzed by a computer. Luminal transit was assessed videofluoroscopically. Control meals moved rapidly (1.9 cm/s) along the jejunum. This was achieved by contractions that occurred at a high frequency (12.8 cpm) and propagated over long distances (9.9 cm). In contrast, the transit rates of the nutrient meals were considerably slower (0.5-1.0 cm/s), the frequency of contractions (5.0-8.9 cpm) and the length of spread of contraction waves (2.6-4.8 cm) were decreased, and the incidence of stationary contractions occurring individually or in clusters was increased. A mathematical model incorporating frequency of contractions and the length of their propagation was used to predict the transit of jejunal contents. The results of correlation tests and of the mathematical model revealed that the length of spread of contraction waves was the most important factor that influenced transit.