The aim of the study was to investigate the correlation between the levelof reactivity in conjunctival provocation test and conjunctival symptoms that develop during the pollinationseason in grass allergic patients. Conjunctival provocation test with grass pollen allergens was performedin 22 patients suffering from pollinosis. During grass pollination season all patients monitored theirsymptoms with Symptoms Score Cards. A parallel measurement of the level of grass pollen count was carriedout on a daily basis by volumetric method. The mean grass pollen count which triggered the reaction inindividual patients depended on the results of conjunctival provocation test. The lowest pollen countlevel was observed in cases of patients with positive conjunctival provocation test at low allergen extractconcentration of 160 and 500 BU/ml, whereas the highest count in cases of 1,600 BU/ml. The differencebetween the results was found to be statistically significant. A threshold grass pollen concentrationfor conjunctival symptoms was established at the level of 22 grains/m (3). We conclude that the patientswith pollinosis and high reactivity in conjunctival provocation test develop conjunctival symptoms earlierduring grass pollination season than the patients who are characterised by lower reactivity during conjunctivalprovocation test.