If it's this one
http://www.viovet.co.uk/Verm-X_for_Rabbit_Small_Animals/c18936/
then the only slightly iffy ingredient is the molasses, not great for guts or teeth. But I doubt the pellets would do any harm fed in a very limited amount, not sure that they'd do much good either though ! There's another pelleted fed with a coccidiostat added, but I cant remember what they are called. I would not feed a medicated pellet, so I'd just clarify with the person that that is not what he/she is referring to.