Worms, Fleas and Ticks
The treatments work. The timing is what catches people out.
Keep the schedule, not the packet
Parasite treatments are straightforward in principle: the right product, given on time, stops a problem before it starts. Where owners run into trouble is the gap — the month that slips to six weeks, the wormer bought last year that has been sitting in a drawer, or the spot-on applied between the shoulder blades of a dog that promptly swam in a lake two days later.
Flea treatments work by either killing adult fleas on the animal, interrupting the flea's life cycle at the egg or larval stage, or both. Most modern products do one of these jobs well; very few do both. The eggs and larvae that fall off your pet live in carpets, bedding and furniture — which is why treating the environment matters alongside treating the animal, and why a single treatment rarely clears an established infestation on its own.
Wormers work differently depending on what they target. Roundworms, tapeworms, lungworm and certain others each respond to specific drug classes, and no single product covers everything. Dogs in particular — especially those that scavenge, eat raw meat or spend time near slugs and snails — may need more frequent or broader coverage than the standard recommendation. Lungworm, spread by slugs and snails, is genuinely serious and not covered by all routine wormers; it is worth asking your vet whether your dog's current product includes it.
Ticks attach, feed, and detach on their own schedule, which can take anywhere from a day or two to over a week. Tick preventatives either repel ticks before they attach or kill them quickly enough to reduce the risk of disease transmission. Removal technique matters too: a tick tool twisted cleanly at the base is the correct method; tweezers, heat and petroleum jelly all risk leaving the mouthparts behind or causing the tick to regurgitate into the bite.
The products licensed for dogs are not always safe for cats — some are acutely toxic — so never use a dog product on a cat without specific veterinary guidance.
If you are unsure whether your current routine covers the risks your animal is actually exposed to, a nurse clinic is a good place to start the conversation.