Garlic

Garlic is an Allium, and the poisoning is mechanistically identical to onion: organosulfur oxidants convert hemoglobin into Heinz bodies, the spleen clears the damaged red cells, and hemolytic anemia follows. The difference is potency. Merck states garlic is three to five times more potent than onion by weight, so gram for gram it is the more dangerous of the two. There is little garlic-specific dosing measured directly in dogs, so the working range is derived from onion's 15-30 g/kg clinical-sign dose divided by three to five, giving roughly 3-10 g/kg. For a 22 lb (10 kg) dog, about 30-50 g of raw garlic -- roughly 8 to 12 average cloves -- sits in the documented toxic band. Garlic powder and dehydrated garlic are far more concentrated by weight, so garlic salt, garlic bread, seasoning blends, jarred minced garlic and marinades all deserve a higher estimate than their weight suggests. The most important correction on this page is the folk remedy. "A little garlic keeps fleas off" has no supporting evidence and is actively unsafe: cumulative daily dosing of small amounts has produced anemia in dogs, and this includes garlic-containing supplements sold as natural pest control. Use a veterinarian-prescribed flea and tick preventive instead. One clove in a stew is unlikely to trigger hemolysis in a large dog, but that is not the same as safe, and it is certainly not safe as a repeated practice. GI signs -- vomiting, diarrhea, drooling, abdominal pain -- come within hours; pale gums, weakness, jaundice, tachycardia, red-brown urine and collapse typically appear at 3-5 days. Call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 (fee applies) with the form, amount and time. Do not induce vomiting at home, and have a CBC repeated at 24 and 72 hours.