Some wormers like Plerion are extremely palatable which makes dosing so much easier, others are more effective against certain worms. Fleas are intermediate hosts for one the tapeworm - Dipylidium caninum therefore tapeworm infestation will re-occur unless control of intermediate hosts such as fleas is undertaken. To make your choice easier wormers effective against Dipylidium caninium are marked. The control of roundworm is most important when worming puppies.