pms-Ondasetron Tablets contain 4 mg of ondansetron base, in the form of ondansetron hydrochloride dihydrate. Also contain the following excipients (alphabetically): corn starch, croscarmellose sodium, lactose, magnesium stearate and microcrystalline cellulose; and a yellow film-coating containing iron oxide yellow, polyethylene glycol, polyvinyl alcohol, talc and titanium dioxide.