A double-masked, randomized, placebo-controlled study was conducted to evaluate the effectiveness of lodoxamide tromethamine 0.1 % eyedrops in preventing inflammatory cell accumulation in the tear fluid of patients with vernal conjunctivitis. A 1-week baseline period was followed by 4 weeks of treatment with either lodoxamide tromethamine 0.1% ophthalmic solution or placebo in 30 symptomatic subjects with vernal conjunctivitis. Cytological evaluation of tear fluid was performed before and after the treatment. In the lodoxamide-treated group, but not in the placebo-treated group, the number of neutrophils (P = 0.051) and eosinophils (P = 0.020) in the tears significantly decreased at the end of 4 weeks when compared with baseline (Wilcoxon-signed rank test). It was concluded that lodoxamide treatment was significantly more effective than the placebo in terms of reducing inflammatory cells in the tear fluid in vernal conjunctivitis. This objective inhibition of inflammatory cells may be associated with clinical relief.