What to Do If Your Dog Eats Onion (Onion Poisoning)

1 Why Onions Are Toxic

The propyl disulfide in onions is the main toxin. It lowers red-cell glucose-6-phosphate dehydrogenase activity, causing oxidative damage to the cells. Damaged hemoglobin precipitates onto the red-cell membrane as Heinz bodies, and both intra- and extravascular hemolysis follow.

2 Symptoms

The dog is depressed with normal visible mucous membranes, mild jaundice of the skin, slightly rapid breathing, and occasional vomiting. A blood count shows a mild drop in red cells, and the smear reveals Heinz bodies on some red cells.

3 Treatment

Use antioxidant therapy, liver protection to lower transaminases, symptomatic antiemetics, and nutritional support, while watching the red-cell count and transfusing if needed. Specifically: IV reduced glutathione 0.1 g/day for 10 days; subcutaneous S-adenosylmethionine 2 mg/kg once daily for 7 days to repair liver cells and lower enzymes; subcutaneous metoclopramide 0.5 mg/kg for vomiting.

Nutritional support: IV 5% glucose 70 ml with ATP 0.2 mg/kg and CoA 50 IU, plus lactated Ringer’s 50 ml; subcutaneous sheep-placenta transfer factor 2 ml and compound butaphosphan 1 ml, throughout treatment. A sharp red-cell drop causes hypoxia, acidosis, and shock and threatens life. Finding Heinz bodies on the smear confirms oxidative damage; onion poisoning drives the red count down sharply while white cells rise rapidly — neutrophilia that, like acute toxemia, hemolysis, or blood loss, points to inflammation or poisoning.