In the UK, the mushrooms generally associated with dog intoxication are amanitas (A. panther and A. fly agaric), as well as the genera Inocybe and Clitocybe (Field Mushroom and Ivory Funnel). Amanitas contain two toxins: muscimol and ibotenic acid. Intoxication can be fatal. The first signs appear one to 2 hours after ingestion: a poisoned dog will exhibit a complete change in behavior including, frenetic agitation, howling, hallucinations, pupil contraction, loss of balance, and convulsions.
Inocybes and Clitocybes are characterized by a high concentration of muscarine, a substance similar to acetylcholine. The first signs appear 2 to 3 hours after ingestion: There may be excessive salivation, nausea, vomiting, diarrhea, difficulty breathing alongside a general state of weakness.
With treatment, the symptoms regress within 24 hours. There is an antidote to treat this type of intoxication (ATROPINE).
There is a clear correlation between the onset time, the intensity of the initial signs, and the severity of intoxication, meaning the more the symptoms they display, the worse the toxicity.
If you suspect your pet has ingested a toxic mushroom: