Used primarily as an anti-amoebic agent, particularly in the treatment of severe intestinal and hepatic amoebiasis caused by Entamoeba histolytica. It is effective in killing tissue-invasive forms of the parasite, though less effective against luminal forms. Due to its toxicity, including cardiotoxicity and myotoxicity, it is generally reserved for acute cases and often followed by a luminal agent like paromomycin or diloxanide furoate to eradicate residual infection. Also investigated for its potential antiviral properties, including inhibition of viral replication in some RNA viruses, and has shown in vitro activity against certain cancer cell lines due to its ability to inhibit protein synthesis. Historically used as an emetic, but this application is obsolete.