Bithionol sulfoxide is a clinically approved antiparasitic drug with the inhibitory against solid tumor growth in several preclinical cancer models.

Bithionol caused dose-dependent cytotoxicity against all ovarian cancer cell lines tested (IC50s: 19 μM - 60 μM). BT treatment resulted in cell cycle arrest at the G1/M phase and increased ROS generation [1]. Both bithionol and bithionol sulphoxide demonstrated in vitro toxicity to Neoparamoeba spp. at all concentrations examined (0.1 to 10 mg/l over 72 h), with comparable toxicity to freshwater observed for both chemicals at concentrations > 5 mg/l following a 72 h treatment [2].