Influenza virus belongs to Orthomyxoviridae family which is considered amongst the most important causes of morbidity and mortality worldwide. Due to the lack of effective drugs and efficient vaccines, exploring for alternative or complementary traditional medicine seems to be crucial in order to prevent the spread of this important threat. In traditional medicine, garlic is one of the most common herbs used in the treatment of various diseases and ailments especially those associated with the respiratory system. In our previous study, we demonstrated significant antiviral activity of garlic extract (GE) on influenza infection using hemagglutination (HA), methyl tetrazolium (MTT) cytotoxity assay and RT-PCR. Current study was designed to evaluate immunofluorescent assay as a reliable and rapid diagnostic test for this infection. An in vitro assay was carried out by infecting MDCK cells with H1N1 influenza A virus (100TCID 50) in the presence/absence of non-toxic concentration of garlic extract (10 µg/ml). The cells were then subjected to fluorescent staining and the fluorescent intensities were evaluated by randomly counting and averaging the 16 fields of each well. The antiviral activity quantification was provided by calculating the proportion of infected cells in which the production of influenza A virus fluorescent antigens was blocked. It was found that rapid direct fluorescent assay has the ability to detect the effect of garlic extract on the replication of influenza A virus at the first steps of infection.