A method for the treatment and/or prophylaxis of a viral infection in a subject is provided wherein the method comprises the steps of providing a therapeutically effective amount of a composition comprising an extract of the fruit of Siraitia grosvenori Swingle and administering the composition to the subject. The fruit from which the extract is derived is Luo Han Guo. The extract comprises at least one thterpene glycoside, which may be in the form of a mogroside compound. The extract has been shown to be effective in the treatment of viral infections such as hepatitis C and HIV. Also provided are pharmaceutical compositions comprising at least one triterpene glycoside, or an analogue, metabolite, precursor, derivative, pharmaceutically active salt or pro-drug thereof.
