Dogs and sometimes cats are poisoned by mouthing certain types of toads. All toads produce venom, but the potency of the venom varies with species and geographic locations. Toad venom is a thick, creamy white, highly irritating substance. It can affect the heart, the nervous system, and the blood vessels. The most toxic species in the US appears to be the giant or marine toad, Rhinella marina (formerly Bufo marinus), an introduced species that is established in Florida, Hawaii, and Texas. It is known as the cane toad in Australia, with a range across the northeastern half of the continent.
Encounters with toads are most common in warm or mild weather. Signs of poisoning vary and range from local effects in and around the mouth to convulsions and death. Local effects include frothy drooling, vigorous head shaking, pawing at the mouth, and retching. They are seen immediately, probably because the venom is extremely irritating. Vomiting is not unusual and may persist for several hours. Severe poisoning, as from Bufo marinus venom, causes life-threatening abnormal heart rhythms, difficulty breathing, a bluish tinge to skin and mucous membranes, and seizures.
There is no specific antidote. Treatment is directed at minimizing absorption of the venom, along with supportive treatment. The mouth should be immediately and thoroughly flushed with large amounts of water. Supportive treatment includes medications to reduce the amount of saliva and to correct the heart rhythm. Oxygen therapy may also be needed.