The 50% antitrichomonal concentration of 7 examined ethers (T. vaginalis strain N. 1/86, Roiron medium, safranine staining, 30 min.) was estimated by means of dose-response curve. The minimal mycostatic concentration (Candida albicans L-45, Geotrichum candidum; 3% Sabouraud agar, 37 degrees C, 24 hr) was calculated with the aid of regression equation. All examined ethers show in vitro a marked antitrichomonal effect comparable with activity of ornidazole or phenol. Mycostatic activity of new compounds is many times higher than activity of phenol, but considerably lower than that of clotrimazole. The strongest complex antitrichomonal and mycostatic effect-comparable to ornidazole or clotrimazole - shows the new derivative N,N-diethylaminoethyl oxime of 1-tioflavone (compound II), which is fairly toxic for mammal.