Nitazoxanide is a nitrothiazole benzamide with anti-parasitic and anti-viral activity. It inhibits pyruvate-ferredoxin oxidoreductase in protozoa and anaerobic bacteria. It inhibits many anerobes in vitro, with MIC₉₀ values of 0.06 µg/ml-4 µg/ml. It inhibits different strains of influenza A virus replication with EC₅₀ values of 1, 0.5, and 1 µg/ml respectively. It is used to treat enteritis caused by Cryptosporidium parvum and Giardia lamblia in children and adults. It is in clinical trials for treatment against COVID-19.