Acute allergic conjunctivitis (AAC) is a common ocular allergic disorder and incident rates as high as 20% have been reported. Although a wide range of therapeutic agents are available for the treatment of AAC, the ideal treatment seems to have remained elusive. Levocabastine, a highly potent specific H1-receptor, appears to offer a promising alternative as a topical single-agent therapy. Levocabastine eye drops have been found to be well tolerated with an adverse-effect profile comparable to placebo and sodium cromoglycate. In addition, ocular levocabastine has been shown to have a rapid onset and long duration of action. The efficacy of levocabastine has been extensively investigated in conjunctival provocation tests and environmental studies. The available data suggest that ocular levocabastine is an effective therapeutic agent. Statistically significant differences in favour of levocabastine have been observed in comparisons with sodium cromoglycate, antazoline/naphazoline and oral terfenadine.