In the framework of preclinical testing of AV0038, ethyl 2-(dimethylaminomethyl)-5-hydroxy-1-methyl-6-(pyridin-3-yl)-1H-indole-3-carboxylate, which showed high efficiency in the prevention and treatment of influenza A/Aichi/2/69 (H3N2) in mice, we have studied the drug solubility and stability in aqueous solutions, metabolic stability in human liver microsomes, stability in blood plasma of mice and humans, binding to plasma proteins of mice and humans, pharmacokinetics and bioavailability in mice, and the acute toxicity and the maximum tolerated dose. It is established that AV0038 has attractive pharmacological properties as anti-influenza drug candidate. The therapeutic doses of AV0038 do not cause acute toxicity in mice. It is expedient to continue preclinical investigations and study the drug metabolism, metabolites, and sub-chronic toxicity in test animals.