Purpose: To measure the inflammatory reaction in the anterior chamber after lens extraction in a rabbit model and to evaluate the effect of nonsteroidal antiinflammatory drugs (NSAIDs) or steroids on the amount of inflammation as measured by fibrinogen levels in the aqueous humor. Setting: Animal laboratory, Goldschleger Research Institute, Tel Aviv University, Sheba Medical Center, Ramat Gan, Israel. Design: Experimental study. Materials: Twenty-six eyes of New Zealand white rabbits had lens extraction surgery. One day later, aqueous humor (∼0.1 mL) was withdrawn from the anterior chamber and examined for fibrinogen concentration. Control rabbits received no treatment (9 eyes) or artificial tear eyedrops (5 eyes). One study group received NSAID drops (diclofenac) (6 eyes), and another study group received steroid drops (dexamethasone-neomycin) (6 eyes). All rabbits were treated hourly for 9 applications. Aqueous humor (∼0.1 mL) was withdrawn from the anterior chamber and examined for fibrinogen concentration 1 day later. Fibrinogen levels were also measured in the aqueous in 8 unoperated eyes. Results: Steroid-treated eyes achieved the lowest inflammatory score, followed by NSAID eyes, artificial tears eyes, and untreated eyes. The mean fibrinogen concentrations in the aqueous humor were 69.1 mg% untreated, 52.0 mg% artificial tears, 18.5 mg% NSAIDs, and 2.8 mg% steroids (P=.002). Conclusions: Measurement of aqueous fibrinogen after lens extraction surgery in a rabbit animal model was simple and provided a useful parameter for precise evaluation of postoperative intraocular reaction. Steroids and NSAIDs were effective in reducing postoperative inflammation. Steroids reduced inflammation to almost undetectable values. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.