Worm eradicator works great and they are fast on delivery within days. I use drontal plus also and prefer it over any. For just maintenance I safe guard once a month 3 days consecutive. I worm pregnant bitches before breeding Drontal or worm eradicator and again with safe guard 2wks before deliver date. Pups get wormed 2,3,4,6wks with just the regular liquid D-worm. At 8wks they get a broad spectrum like Drontal plus or Worm eradicator.