Will dewormer work on a very , very old dog with many health issues?

He is not ours and I have suggested putting him down, but owner refuses. Everyone is recovering from loss of income so no extra money for vets and we have 2 healthy dogs. The old dog has taken over their living area and bedding.

Wormers work on ANY dog....they kill worms....period.& one type will NOT kill all species of worms.Responsible adults worm dogs regularly=twice yearly is fine.

If the dog has health issues, then I think you ought to have a fecal done by the vet first to even see if the dog has worms. You don't have to take the dog into the vet's, just a stool sample. The cost is under $20. My vet charges $13.20 for a fecal.For healthy dogs, Safeguard is the same chemical as Panacur which the vets use. Another choice is the chemical Pyrantel Pamoate which is also used by vets and comes in several brands of wormers, ie D-Worm

Yes, dewormers will work on a very very old dog. You can purchase an over-the-counter dewormer, however be aware that adverse reactions are possible with any deworming product. Roundworms and hookworms are the primary parasites you need to focus on in dogs, however there are other GI parasites which could cause problems so simply using an over-the-counter product without a fecal exam may not cover all the parasites a dog has. While vets will run fecal exams and dispense medications for regular clients, you cannot simply take a fecal sample to a vet's office when they have never seen the animal before as the law requires that they have a client-patient-doctor relationship and have seen an animal within a reasonable amount of time before they can provide any veterianry care for that animal. If your concern is for your dogs, most heartworm prevenatives and even some of the topic flea and tick preventatives now treat for GI parasites. So if your dogs are on a monthly heartworm preventative you are likely treating them for roundworms and hookworms monthly.