Ahhh, Dr.Google again. There are a great number of websites from so-called experts and pet stores recommending garlic as a dewormer for dogs. Some sites go as far as giving weight-dependent doses. This practice is touted as a “natural,” or “holistic” approach to pet care.
Let’s remember that natural, meaning compounds found unaltered in nature, aren’t always safe. If a human being consumes one half of a death cap mushroom (Amanita phalloides,) the results are almost fatal.
Garlic is a member of the genus Allium, which also includes onions and chives. These plants contain compounds called sulfoxides. Sulfoxides are at best dangerous, and quite often fatal, for pets. Exposure to raw, cooked and/or powdered garlic causes toxicity. The initial signs of poisoning are gastrointestinal in nature; vomiting, drooling and inappetance often accompanied by lethargy. The sulfoxide compounds are working inside the animal causing red blood cell destruction resulting in significant anemia. If enough time passes without care, renal (kidney) failure can result.
Please remember to read labels to make sure anything given to pets is garlic and onion free. Sneaky sources can be baby foods and treats. If you suspect that your pet may have ingested a compound containing garlic or onions, consult your veterinarian immediately, or call pet poison control.