The effect of poloxamer 407 onPseudomonas aeruginosaadherence to cultured epithelial cells from rabbit corneas was investigated. Three methods of bacterial quantification were used to assessP. aeruginosaadherence: scanning electron microscopy (SEM) counts, radioactivity counts, and viable bacteria counts. Confluent monolayers of rabbit corneal epithelial cells were incubated in agitation for 30 min at room temperature with H3-labeled or nonradiolabeledP. aeruginosa(1010bacteria/ml) in a solution of poloxamer 407 [2% or 4% in phosphate-buffered saline (PBS)] or PBS as control. Cell monolayers were washed to remove nonadherent bacteria and fixed with 2.5% glutaraldehyde and processed for SEM or processed for radioactivity counting or for culture on agar plates. The results showed that both solutions of poloxamer 407 inhibited ∼75% of the bacterial adherence to epithelial cells (p < 0.05). Similar percentages of bacterial inhibition were obtained using the three methods of bacterial quantification. The use of an antiadherent agent such as poloxamer 407 in eye drops could possibly be a prophylactic approach toP. aeruginosakeratitis.