Wisconsin Restaurant Accidentally Serves THC-Laced Food, Sickening 85 People | Research

The takeaway

A Wisconsin restaurant accidentally used hemp-derived THC cooking oil, causing 85 people to experience THC intoxication symptoms including dizziness, sleepiness, anxiety, and altered perception over three days.

Public health officials, food safety regulators, restaurant operators, hemp product manufacturers

85 people intoxicated from restaurant food over 3 days

What the researchers found

After a restaurant ran out of cooking oil and used oil from a shared kitchen that contained hemp-derived delta-9-THC, 85 people met the case definition for THC intoxication. Affected individuals ate pizza, garlic bread, cheese bread, or grinder sandwiches and developed symptoms within 5 hours. Seven were transported to hospitals.

Why it matters

This MMWR report documents a mass unintentional THC exposure event that illustrates the regulatory gaps around hemp-derived THC products in food preparation settings. As these products become more common, the risk of accidental exposure increases.

The numbers in context

85 cases; 7 hospital transports; symptoms occurred within 5 hours; affected products: pizza, garlic bread, cheese bread, grinders; 3-day exposure period (October 22-24, 2024).

How the study worked

Outbreak investigation by Public Health Madison & Dane County using online food/symptom questionnaire distributed via press release and social media. 107 valid responses analyzed; 85 met case definition requiring food exposure and at least one THC intoxication symptom within 5 hours.

What this study cannot tell us

Case ascertainment relied on self-report via online questionnaire. Actual number of affected individuals likely higher than 85. No THC blood testing was performed on most affected individuals. The exact THC content of the contaminated oil was not reported.

How to read the evidence

MMWR outbreak investigation with self-reported case ascertainment; well-documented exposure pathway.

When this study was published

2025 publication of October 2024 incident

The bigger picture

Hemp-derived THC products exist in a regulatory gray area in many states. Shared commercial kitchen spaces create cross-contamination risks. This incident highlights the need for clear labeling requirements and storage protocols for THC-containing ingredients in food service.

Questions still open

How many other shared commercial kitchens have similar cross-contamination risks?
What labeling and storage regulations would prevent such incidents?

Common questions

Can you get high from restaurant food?

In this documented incident, a Wisconsin restaurant accidentally used hemp-derived THC cooking oil from a shared kitchen, causing 85 patrons to experience THC intoxication symptoms including dizziness, sleepiness, and anxiety. Seven were hospitalized.

Is hemp-derived THC in food regulated?

This incident highlights regulatory gaps. The THC was in cooking oil from a shared commercial kitchen where another vendor made THC edibles. The CDC report recommends clear labeling, locked storage, and regulations for THC-containing ingredients in food businesses.

Read the original research

Tetrahydrocannabinol Intoxication from Food at a Restaurant - Wisconsin, October 2024.

MMWR. Morbidity and mortality weekly report, 74(27), 439-442

View on PubMed ↗Publisher’s paper ↗

Citation

Kita-Yarbro, Amanda; Moccero, Stefanie; Brobston, Katie; Goebel, Jacob; Banks, Janice Block; Vogt, Christy; Schumann, Casey; Grande, Katarina M; Olsen, Julia; Armstrong, Bonnie. (2025). Tetrahydrocannabinol Intoxication from Food at a Restaurant - Wisconsin, October 2024.. MMWR. Morbidity and mortality weekly report, 74(27), 439-442. https://doi.org/10.15585/mmwr.mm7427a2