According to WebMD, puppies should be wormed at 2,4, 6 and 8 weeks of age. An adult dog should then be placed on a monthly heartworm medication to protect against parasites.
Dog owners should pay attention to the health of their pets and note any changes in behavior that could indicate worm infestations, suggests the Upper Valley Veterinary Clinic in Rexburg, Idaho. Owners should always seek the advice of a vet before deciding to self-worm a puppy. Worm medications can be harmful to puppies with respiratory infections, that are chilled, are in unsanitary conditions or that have been weaned from their mothers too early.