Please make sure you treat your dogs for lungworm, this is fast becoming a serious problem in the UK with dogs affected all over the country. I swap worming products once a year to ensure my dogs have been treated for pretty much everything, and it also helps prevent parasites building up a resistance to any one treatment. Lungworms can be picked up from dogs eating snails and slugs, but also from their trail, for example, if a slug/snail goes across a dogs water bowl. It can also be picked up from your dog eating the faeces of another host animal, fox poo, sheep poo etc. Don't be complacent, this is a killer so make sure you treat your dog, and other pets/animals effectively to guard against it. I nicked this list off a friend of mine which gives a brief run down of the different treatments available, and what/how they are effective: Drontal Plus will cover all intestinal worms found here in the UK, but does not touch Heart/Lung worms, or anything else such as ticks or fleas. It appears Panacur is fine for Round worms and Tape worms. It will eliminate Lungworm, but cannot be used as a preventative. To get rid of Lungworm it takes at least a week's course rather than a single dose. Milbemax Like Panacur is a broad spectrum wormer which can also be used as a preventative for Lungworm, in normal doses. But again like Panacur needs high doses if the worm has become established. Milbemax should NEVER be used for Collie breeds, and can be a problem with other breeds, so needs monitoring (as any medication should be.) Advocate can be used as a cure, and is again a broad spectrum wormer and also controls fleas, ear mites sarcoptic mange and demodicosis, but to my knowledge does not touch Ticks or I think Tape worms. Frontline controls fleas and ticks but does not touch worms. Final note, read up on the products you are using, some are less effective than others. You may need a veterinary prescription to order online, your vet should issue these without any problems, without charge or for a small charge only. If not, shop around for a different vet, and compare prices of the different products. The stuff off the shelf at any pet store is ineffective against pretty much everything. Natural foods that help guard against infestation include garlic, pineapple, and to a lesser extent, mint, fenugreek and turmeric. Edited to remove the part about Advocate being used as a preventative, as, although it is stated as being a preventative on several sources, it isn't stated as such on Bayer's own website, nor is it listed as being a preventative treatment with the list of active ingredients. If in doubt, make sure you seek advice from your vet in the first instance.