Most cancer drugs used in a clinical setting are insufficiently effective and insufficiently safe. This prompts the search for novel substances to fight cancer. The aim of this study was to explore the effects of dihydrobromide 2-(3,4-dihydroxyphenyl)-9-diethylaminoethylimidazo[1,2-a] benzimidazole (RU-185) on the growth and metastasis of experimentally induced transplantable Lewis lung carcinoma (LLC). Fifty-five C57/Bl6 male mice (weight 18–20 g) were subcutaneously inoculated with LLC cells. The tested substance (0.5 ml) was administered intragastrically at 50, 220, and 500 mg/kg (groups 1, 2 and 3, respectively) once a day for 10 days starting at 48 h after inoculation. The control group received normal saline. Intragastric administration of the tested substance resulted in significantly longer survival in group 2 only (162.3%) and in the significant reduction of tumor size on day 1 after treatment in all groups. After the end of treatment, tumor sizes in groups 2 and 3 were 3.4 and 1.3 times smaller, respectively, on day 7 and 2.2. and 1.3 times smaller, respectively, on day 14 than in the control group (р < 0,05). The growth delay rate was sustained in group 2 by day 14 after the end of treatment; tumor regression was observed in 20% of the animals. The number of metastases in the lungs was lower in groups 1 and 2 than in the control group (2.6 and 3.1-fold, respectively), and the metastasis inhibition was 68.1% and 80%, respectively. The tested substance RU-185 has an anticancer effect in mice: it results in longer survival, slower growth of the primary tumor and fewer lung metastases of Lewis lung carcinoma.