Learn how to de-worm puppies and the importance of this. Nearly all puppies are born with worms transmitted from their mother. Most of the time we won't see them in the stool. This is why deworming is so important at a young age. Most deworming programs start as early as 2-3 weeks of age. Deworming kills the adult stage of the worm. As eggs hatch, additional deworming is necessary. For this reason, your veterinarian will likely recommend multiple doses.