Verdict: No, toxic
Onions are highly toxic to dogs and should never be fed to them in any form. They contain compounds that damage red blood cells, leading to a serious condition called hemolytic anemia. If your dog has ingested any amount of onion, seek immediate veterinary attention as this is a medical emergency.
N-propyl disulfide causes oxidative damage to red blood cells, leading to hemolysis (destruction of red blood cells) and Heinz body anemia. It interferes with an enzyme called glucose-6-phosphate dehydrogenase (G6PD) in red blood cells.
N-propyl disulfide