Using a laser flare-cell meter, the anti-inflammatory effect of diclofenac sodium drops was evaluated after argon laser trabeculoplasty in a double-masked placebo-controlled study. Fifty-three eyes with pseudoexfoliative (43 eyes) or pigmentary glaucoma (10 eyes) were randomly assigned to treatment (n = 27) or placebo (n = 26) groups. Diclofenac (0.1%) or placebo drops were administered once before and after trabeculoplasty and then four times daily for a total of 4 days. Visual acuity, intraocular pressure, and anterior chamber flare, measured with the laser flare-cell meter, were evaluated before trabeculoplasty, 3 and 6 hours after trabeculoplasty, and 1, 2, 4, 7, and 14 days after trabeculoplasty. Flare increase after argon laser trabeculoplasty was completely blocked by 0.1% topical diclofenac and the mean of maximal flare increases was reduced significantly in the diclofenac group. Therefore, 0.1% diclofenac drops represent a very efficient anti-inflammatory therapy after argon laser trabeculoplasty.