Ovex Tablet Ovex tablets is for the treatment of one person only. Though it is recommended that the whole family is treated with Ovex at the same time to prevent re-infection & to prevent the infection to spread further. A single dose will treat the threadworms but may not get rid of the eggs which means that treatment should be continued until the condition is fully treated. How Does Ovex Work? Ovex contains the active ingredient Mebendazole. Mebendazole prevents the threadworms from absorbing sugar which kills them within a matter of days. As Mebendazole does not destroy the eggs, treatment may have to persist for as long as it takes the infection to clear. How To Take Ovex Adults & children aged 2 & over: One tablet to be chewed or swallowed whole. Ovex should not be taken by pregnant or breastfeeding mothers.