H1-antihistamines (H1A) have been used for more than 50 years in the treatment of allergic pathology. Their widespread consumption and the growing pharmaceutical offer is noteworthy. Despite this, we have not found any study on the compliance of these drugs in the scientific literature reviewed. The aims of this study are to evaluate compliance with the prescription of H1A in a sample of allergic patients diagnosed as pollen rhinoconjunctivitis (PRC), and to evaluate the possible association between the degree of compliance and certain patient-dependent parameters (age, sex, cultural level, knowledge of the prescription and treatment [duration, number of drugs, posology, method of administration and appearance of adverse drug reactions]). The sample size was 300, and 164 were attended. Of these 164 patients, 123 claimed to have taken correctly the H1A prescribed by the allergologist. Of the group of patient claiming to have followed treatment correctly, only 8 patients did not remember the number of packs of H1A bought, nor their price, nor the appearance of the tablets (or solution). Regarding the frequency of use, 101 patients took the H1A daily, and the remaining 22, depending on symptoms. Administration of the H1A was always oral-tablets in 114 cases and solution in 9. The compliance we have found is at a medium level, similar to that reported in other studies (although on other drugs), and no significant differences were found in relation to the parameters studied.