Seaweed is safe for dogs
Seaweed is safe for dogs to eat. It is high in fiber, potassium, iron, calcium, magnesium, and iodine. Different forms and preparations of seaweed (e.g. nori, kelp) are generally safe, but avoid seaweed prepared with seasonings such as salt or garlic. Always feed in moderation and make sure not to give large pieces since they can be chewy and cause choking.
It is important, however, to be cautious with wild seaweed that you might find along the coast. Wild seaweed can be salty which can lead to dehydration. More importantly, seaweed that has dried up in the sun, will absorb water as your dog digests it. This will cause it to expand in the stomach or intestines, potentially leading an obstruction. An obstruction can cut off blood flow to your dog’s bowels, leading to serious harm or death. Symptoms of an obstruction include, vomiting, diarrhea, loss of appetite, lethargy, and weakness. Contact your veterinarian if your dog has eaten dried wild seaweed.