The seeds must be ground if you want to take advantage of the natural worming properties. Info I found on pumpkin seeds as a natural wormer:
"Pumpkin seeds, freshly ground. Try to grind up pumpkin seeds finely right before feeding as opposed to grinding them several days in advance. If you must grind them in advance, keep them in a sealed container in the freezer and take out a day's portion right before feeding. You don't want moisture to enter the seeds. The seeds need to be raw, not baked and salted. Give 1/4 to 1 teaspoon per meal to your animal, depending on size (a cat will get 1/4 teaspoon, but a German Shepherd would get 1 teaspoon). This is effective against tapeworms and very safe."
From another site:
"Ground raw hulled Pumpkin Seeds are a good natural wormer. There is a coating on the seed that paralyzes the worm and then the worm can be expelled by the digestive action of the gut. It is good to feed something that will cause the animal to have a slight diarrhea (flush) like molasses or skim milk about an hour or two after the seeds have been eaten."
*Note- the seeds only paralyze the tapeworm and roundworm*