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The adsorption of particles from a steady-state flows of dilute suspensions from infinite reservoirs over the mucous surface of intestinal strips were quantitatively studied.The micron-size particle systems included positively and negatively charged latex spheres and particles coated with neutral, positively and negatively charged polymers. The suspensoids were characterized by zeta potential measurements. An in vitro setup and technique likened to a thin falling liquid film system was developed wherein an excised intestinal segment cut lengthwise is spread on a plastic flute and positioned at an incline, and a suspension is allowed to flow down the intestinal strip. The falling liquid film was estimated to be 54 $\\mu$m in thickness from nonsteady-state flow kinetic experiments. The logarithm of the fraction of nonadsorbed particles remaining in the liquid film decreased linearly with intestinal length at all flow rates employed. The fraction adsorbed decreased with increasing flow rates on account of the shorter transit times. The steady-state region of the fraction of nonadsorbed particles remaining versus time plots persisted for a relatively long time indicating the existence of a particle concentration gradient along the length of the intestinal strip. The fact that the fraction of particles adsorbed was not affected by particle concentrations ranging from 4.5-14 $\imes 10\\sp6$ particles per ml suggests that there are sufficiently available unoccupied surface area for incoming particles to be adsorbed onto mucus. It has been estimated that no more than 5% of the area of the intestinal strip is occupied by adsorbed particles. The mass transfer resistances of negatively charged particles decreased with the addition of sodium chloride and approached the minimum resistance obtained by the positively charged, polybrene-coated latex particles, whose mass transfer resistance was independent of electrolyte concentration. Passage of particles over the potential energy barrier is required for the successful collision and tight binding with mucus. The thin hydrodynamic boundary layer within the thin liquid film is estimated to be 0.7 $\\mu$m. There appeared to be entropic repulsion between the neutral dextran-coated particles and the mucus on the intestinal strip although the particle surface was fouled by mucus which sloughed from the intestine. (Abstract shortened with permission of author.)