Objective We investigated the early posttreatment effects of two steroidal anti‐inflammatory ophthalmic drugs on blood‐aqueous barrier (BAB) breakdown by paracentesis in dogs. Animal studies We studied 21 healthy beagles with normal eyes. Procedures Controlled anterior chamber paracentesis (0.5 mL) was performed in one eye of each dog. Control group dogs (n = 7) received no medication, whereas those in the treatment groups received a topical anti‐inflammatory medication (difluprednate [DFBA] ophthalmic emulsion 0.05% [n = 7] or betamethasone [BMZ] sodium phosphate ophthalmic solution 0.1% [n = 7]) at 0, 15, 30, and 45 minutes after initial paracentesis in the paracentesed eyes. Secondary aqueous humor (AH) was collected 60 minutes after initial paracentesis. Protein and prostaglandin E2 (PGE2) concentrations in AH were determined using the bicinchoninic acid assay and commercially available immunoassay kit, respectively. All mean values in the three groups were compared using analysis of variance followed by Tukey's post hoc test. Results Aqueous protein and PGE2 concentrations were markedly increased at 60 minutes following paracentesis. Both concentrations in the secondary AH of the DFBA group were significantly lower than those of the control group; however, treatment with BMZ had no significant effects. Conclusions Early postparacentesis treatment with DFBA was more effective than that with BMZ for reducing aqueous protein and PGE2 contents in dogs with paracentesis‐induced BAB breakdown. DFBA may be an appropriate treatment during the early stage of anterior uveitis caused by intraocular surgery in dogs.