Maintain an effective worm control program for your pets with preventative treatment every 3-6 months. Ideally they should be wormed against roundworm from a young age, and adult pets should be treated against roundworms and tapeworms. Most clinics require that the pet be registered at the clinic before dispensing worming treatments; the pet also needs to have been seen within the last year to ensure that the pet's weight has been taken into account.