Adenoviruses constitute a clinically important family of human pathogens. Due to their wide tissue tropism, adenoviruses are able to induce different diseases from moderate respiratory disorders to fatal outcomes in patients with immunodeficiencies. The authors present the results of a trial of the antiviral activity of the new drug Ingavirin [2-(imidazole-4-yl-ethanamide) pentandioic-1,5 acid] against human adenovirus type 5 on an animal model. Ingavirin is shown to decrease an adenoviral infectious titer in the liver and lung of neonatal Syrian hamsters (by approximately 1 log10 TCID50 as compared to the control) and to reduce the sizes of liver inflammation foci by 2-fold. Furthermore, it also decreases the count of virus-infected cells detectable by morphological analysis. Hepatocytes from Ingavirin-treated animals appear intact unlike strongly vacuolized cells from the animals given placebo. The findings make it possible to regard Ingavirin as a promising agent of the combination therapy of human adenovirus disease.