For 20 years, Drontal has been overwhelmingly vets' first line choice of wormer. Like all Drontal tablets, it works with a single dose, and can be given with or without food. For dogs, the new artificial beef flavour makes it less like a treatment, and more like a treat! Drontal is Britain's number 1 Wormer. Most types of intestinal worm which can infect cats and dogs in the UK have the potential to cause serious damage to the animal’s health if left untreated. Remember that some tapeworms can grow up to 5 metres in length. But even more alarming is the fact that some worms can also infect humans.