Background: Fatal cases of exposure to paralytic shellfish toxins and palytoxins have occurred in companion animals but are poorly described., Methods: We describe one case of paralytic shellfish poisoning (PSP) and three cases of palytoxin poisoning in dogs., Results: Mild PSP occurred following ingestion of crab while walking on a beach. Analysis confirmed the presence of paralytic shellfish toxins, particularly decarbamoyl saxitoxin, in clinical samples and marine organisms. This case occurred shortly after an outbreak of PSP in dogs on the eastern coast of England. Palytoxin poisoning occurred in a dog after it chewed coral removed from an aquarium. Signs included collapse, hypothermia, bloody diarrhoea and respiratory distress. The dog was euthanised due to rapid deterioration and poor prognosis. Palytoxin was not detected in a premortem blood sample. Two other dogs in a separate incident developed only mild signs (fever and respiratory distress) after suspected exposure to aerosolised palytoxin and recovered within a few hours., Conclusion: Cases of PSP are episodic and not common in dogs. Cases of palytoxin exposure are reportedly increasing in humans, and there is presumably also an increased risk to pets. There is no specific treatment for PSP or palytoxin poisoning., Competing Interests: Competing interests: None declared., (© British Veterinary Association 2020. No commercial re-use. See rights and permissions. Published by BMJ.)