8-Hydroxyquinolinols chlorinated on the number 5 and/or 7 carbon atom(s). They are antibacterial, antiprotozoal, and antidiarrheal, especially in amebiasis, and have also been used as antiseborrheics. The compounds are mostly used topically, but have been used also as animal feed additives. They may cause optic and other neuropathies and are most frequently administered in combination with other agents.