Introduction: The covid-19 pandemic caused by the acute respiratory syndrome coronavirus (SARS-CoV-2) has affected millions of people around the world.Respiratory viral infections make patients susceptible to other infections and lead to increased mortality.The meta-analysis showed that the antibiotic azithromycin was prescribed the most to prevent and deal with secondary infections in patients with Covid-19.Despite the beneficial effects of antibiotics in preventing the growth of pathogenic bacteria and causing disease, these compounds can have adverse effects on the intestinal microbiome and change the intestinal bacterial population.New research suggests that there is a complex two-way relationship between the gut microbiome and the host that plays a role in human health as well as in disease pathogenesis. Changes in the composition and function of gut microbiota can affect gut permeability, digestion, metabolism, immune responses, and memory and learning. Based on this, in the present study, the effect of the antibiotic azithromycin on the gut microbiome and memory recall was investigated. Methods: In this experimental study, adult male Wistar rats weighing 220-250 grams were divided into control and antibiotic groups.In the control group, normal saline (0.6 ml) and in the antibiotic treatment group, azithromycin (15 mg/rat with a volume of 0.6 ml) was gavage daily for 7 days.In order to investigate the effect of azithromycin on the intestinal microbiome, in both groups of the PCR test (to identify and investigate three bacterial species:Enterococcus faecalis and Lactobacillus acidophilus and E.coli) And stool culture was used before and after treatment.At the end of the treatment, the memory was evaluated with the help of the passive avoidance test and the new object recognition test and motor activity was checked by the locomotion device. Results: In the passive avoidance test, azithromycin gavage significantly reduced memory recall compared to the control gro
