Objective: To evaluate the clinical efficacy and side effects of two different concentrations of KT solutions (0.5% and 0.4%) in allergic conjunctivitis patients. Material and Methods: Thirty-six patients (20 females and 16 males) who did not have any ocular or systemic disorder other than allergic conjunctivitis were enrolled in the study, ages of the patients ranged from 24 to 35 years. Patients randomly received treatment to one eye with KT 0.4% and to the other eye with KT 0.5%. Patients were evaluated after one week and symptoms, signs before and after the treatment, drug related adverse effects and intolerance were assessed. Results: Although the signs and symptoms of the allergic conjunctivitis in both eyes improved significantly, it did not recover completely in 77.8% of the patients. Either concentrations of the KT solutions did not cause any adverse effect or significant intolerance that might cause cessation of treatment. Comparable mild drug intolerance for both KT solutions, was reported by 41.7% of the cases while 50.0% of the patients reported better tolerance for KT 0.4%, 8.3% of the patients reported better tolerance for KT 0.5%. Conclusion: Both concentrations of the KT solutions provided partial clinical improvement of allergic conjunctivitis but did not cause any adverse effect. This study suggests that KT 0.4% has better tolerance and is as effective as KT 0.5%; however drug intolerance still remains as an issue.