Objective: to study the clinical and laboratory manifestations of acute intestinal infections of bacterial etiology in hospitalized children, depending on the etiology, age, topic of the lesion, and complications.A cohort clinical study of 570 children hospitalized from January to October 2019 in the infectious wards of Children's Clinical Hospital No.9 in Moscow was conducted. Studies included routine laboratory methods, bacteriological analysis of feces, Latex test, ELISA, PCR to detect pathogens, serological reactions to detect specific antibodies in blood serum. Two groups of patients were specially formed to compare the features of the course of bacterial diarrhea without hemorrhagic colitis (n = 111) and with hemorrhagic colitis (n = 125).Among 33.2% of cases of deciphered etiology of bacterial diarrhea, Salmonella was isolated in 14.6%, Campylobacter — in 4.7%, Shigella — in 3%, in other cases — conditionally pathogenic flora. Salmonellosis and Сampylobacteriosis with the same frequency are recorded in children in the age groups of 1—3 and 3—7 years, in half of the patients proceed as enterocolitis (58 and 52%, respectively). Shigellosis is diagnosed in children older than 1 year of life with the same frequency in age groups 1—3, 3—7 and older than 7 years, a third of patients (35%) develop severe forms.In most cases (83.2%), a complicated course of bacterial diarrhea was detected, more often dehydration 1 and 2 degrees (36.5%), acute respiratory viral infections (19.6%), mesadenitis (11.2%), community-acquired pneumonia (4.6%).Enterocolitis is the topic of lesion in half of the children, and every 5th patient develops hemorrhagic colitis (21.9%). In 44% of cases of established etiology of hemorrhagic colitis, Salmonella was confirmed. Hemocolitis also develops more often with shigellosis, campylobacteriosis and clostridiosis. In the group of bacterial diarrhea with hemorrhagic colitis, significant differences were revealed compared with the group without hemocolitis: by the frequency of development in children under 3 years of age; by the duration of treatment in a hospital; by the frequency of mesadenitis; by the content of stab neutrophils in the hemogram, reflecting a more pronounced inflammation in hemorrhagic colitis.Thus, bacterial diarrhea in children remains relevant due to the severity of inflammation, the incidence of complicated course and hemorrhagic colitis, which requires hospitalization.