Poisoning Outbreak: Aconite Poisoning at Markham, Ontario Restaurant

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The Poison Lab: Outbreak – Markham Aconite Poisoning

On August 29, 2022, twelve diners at a Markham, Ontario restaurant fell critically ill with vomiting, numbness, and life-threatening arrhythmias. The culprit? A deadly plant toxin: aconite.

In this episode—the first of a new Poison Lab Outbreak series—we go inside the Markham mass poisoning case. Join host Ryan Feldman, clinical toxicologist and emergency medicine pharmacist, as he investigates how a rare and lethal toxin ended up in a restaurant spice jar and nearly cost lives.

You’ll hear firsthand from the experts who responded to the outbreak:

• Dr. Jessica Kent, toxicology fellow at the time at the University of Toronto
• Dr. Abinhay Sathya, intensivist at Markham Stouffville Hospital
• Dr. Margaret Thompson, toxicologist and on-call consultant for the Ontario Poison Centre
• Dr. Randy Purves, research scientist at the Canadian Food Inspection Agency (CFIA)
• Bryn Shurmer, MS- analytical chemist at the Canadian Food Inspection Agency (CFIA) 

Together, they walk us through the outbreak timeline—from the first patients in VT to the public health investigation that uncovered a mislabeled spice bag full of pure aconite root.

Looking for timestamps?

A fully timestamped version of the episode—so you can jump to any topic—is available to our supporting members.

💡 Key topics:

• Clinical presentation and toxic effects of aconite
• Challenges in mass poisoning recognition and coordination
• The crucial role of poison centers in outbreak response
• Public health trace-back to contaminated galangal powder
• Lessons for emergency departments and toxicologists

📍 Resources & Mentions:

• Case series about the incident written by Dr. Kent, Sathya, and Thompson
• Twitter/X post by Dr. David Juurlink that helped disseminate early info
• The Poison Lab previous aconite episode: Open and shut (Mystery Case #31)
• Paper written by Ryan, Dan McCabe, and Crissy Lawson

🎧 Listen now at: www.ThePoisonLab.com

💬 Have thoughts or questions? Connect on Instagram @tox_talk, Twitter @LabPoison, or email [email protected].