Here is a quote from the book "The Nature of animal healing" by Dr Martin Goldstein: "To judge by your local vet's stern insistence on regular heartworm pills for your dog, you'd think we're in the midst of a brutal epidemic, leaving piles of the dead in its wake. I think there's an epidemic, too, but of a different sort: of disease-causing toxicity instilled in our pets by heartworm preventative pills. Granted, heartworm is a serious condition. An infected mosquito bites your dog, injecting microscopic worms that first hibernate, then gain access to his bloodstream. The worms find their way to the heart, where they grow to as long as twelve inches, constricting the heart's passages and causing symptoms that range from coughing to labored breathing to heart failure. If the image of giant worms literally blocking the life blood of your dog isn't horrifying enough-and it can seem more so when viewing a real heart preserved in a jar of formalin, on display in a veterinarian's office as a sales tactic for heartworm preventative-the fact that they spawn hundreds of thousands of baby larvae, called "microfilaria," which circulate through the bloodstream, is nothing short of grotesque. A few caveats are in order, however. Only a small percentage of dogs who get heartworm die of it, especially if they're routinely tested twice yearly for early detection. Even in untreated dogs, after a period of uncomfortable symptoms, the adult worms die. The microfilaria do not grow into adult worms on their own. To reach the next stage in their life cycle, they have to be sucked back out of the body by another mosquito, and go through the other stages of their maturation process withih the mosquito. Only when that mosquito alights again on a dog and bites it can the microfilaria reenter the bloodstream with the ability to grow into adults. The chances of a microfilaria-infected mosquito biting your dog the first time are slim. Of it happening to the same dog twice? Very slim. And after two decades of pervasive administration of heartworm pills in the U.S., the chances of your dog contracting heartworm in most parts of this country even a first time are slimmer still. Early in my career, I saw and treated hundreds of cases of heartworm disease, most with routine medication, yet witnessed only three deaths. By comparison, we're seeing cancer kill dogs on a daily basis. To my mind, the likelihood that toxicity from the heartworm pills is contributing to the tremendous amount of immune suppression now occurring, especially in cases of liver disease and cancer, is far greater and more immediate than the threat of the disease they're meant to prevent. The most common form of hearworm prevention is a monthly pill taken just before and during mosquito season. It's toxins-ivermectin, for example-sweep through the body, killing any microfilaria that have been introduced by mosquito bites in the previous month, and thus preventing the growth of adult worms. Some brands also contain other toxins to kill intestinal parasites. The other approach to treatment is with daily dose of the drug diethylcarbamazine, starting several weeks before mosquito season. The drugs called for in either course if treatment are, simply put, poisons. Unfortunately, while they kill of microfilaria, they have the toxic effects of poisons, and can be especially damaging to the liver.I've saved a product evaluation for diethylcarbamazine mixed with oxibendazole, a preventative also used for hookworms. The evaluation, published by the company itself in a medical journal, reported that of 2.5 million dogs given the stuff, the company received only 176 reports of problems, including cases of liver toxictity and fatalities. To me, 176 is too many. But also, how may more went unreported? The evaluation concludes, "Of course, not all incidences are reported to the manufacturer, so the true magnitude of occurences is really unknown." The manufacturer would argue, no doubt, that many of the symptoms I've seen cannot be linked in any provable way to any of the heartworm preventatives. Perhaps-though the anecdotal evidence has long since persuaded me not to put dogs on the stuff. But I have seen one obvious, immediate effect of these once-a-month preventatives in case after case: when you give a dog that pill, over the next few days, whereever he urinates outside, his urine burns the grass. Permanently! In some cases, you can't grow grass there until you change the soil. What, I wonder, can it be doing internally to your dog in that time? When the first daily preventative came out, my brother and I witnessed evidence of hemorrhaging in the urine of several dogs put on them. We stopped the medication; the bleeding stopped. We started it up agin; the bleeding resumed. When we reported this to the manufacturere, we were informed that the company was aware of the problem from other complaints. Aware-but not about to pull its product from the shelves. All we could do was to stop giving the medication ourselves to the dogs we treated. Since then, the company has changed the product, diminishing this side effect and bringing it into the realm of acceptability for use in areas of high heartworm incidence. The dogs I treat from puppyhood receive no heartworm preventative pills. It may be said, of course, that I practice in an area where cases of heartworm are pretty infrequent. But while my clinic is in Westchester County, just north of New York City, my practice encompasses patients from around the country. In the last decade, 98 percent of my patients, on my recommendation, have not been given heartworm preventative. In that time, I've seen less than a handull of clinical cases. Two of them I treated herbally, starting with heart support supplements (a heart glandular, vitamin E, co-enzyme Q10) and regular doses of black walnut, an herb known to kill parasites. (It comes in a liquid extract form; I recommend putting a dropperful in the food or mouth at each meal.) The third I treated medically, with a new drug (Immiticide) reported to be a lot less toxic than intravenous arsenic, at a lower-than-recommended dosage. All three are clinically normal-no evidence of heartworm recurrence-years after treatment. As a precaution, I recommend that all dogs be tested twice a yearfor hearworm. For clients who insist on a more active form of prevention, I suggest doses of black walnut given tow to theree times a week, as I've actuallyreversed clinical heartworm with it. (For a thirty-pound dog, one capsule three times weekly during mosquito season in areas that have reported any incidence of heartworm.) We also use a homeopathic nosode. In areas where the chances of heartworm exposure appear greater than those in my own - like southern Florida and the Bahamas, where the chances of contracting it are high- I recommend adding to this regimen the conventional daily heartworm pill, given three times weekly. Veterinarians trained in homeopathy can get your pet on a good nosode prgeam for heartworm prevention.