An outbreak of poisoning associated with chocolate bars and other products containing psychoactive ingredients led to well over 100 cases of severe illness across 34 states, researchers with the Centers for Disease Control and Prevention and other institutions said in a new paper.

The poisoning outbreak linked to so-called microdosing products also resulted in 73 hospitalizations, 29 intubations, and two deaths, according to the paper, published by the CDC’s in-house journal on April 9.

“Consumers should be aware that microdosing psychedelic products can cause severe illness or death and that recalled products should not be sold, purchased, or eaten,” the researchers stated.

Diamond Schruumz, which produced many of the items in question, did not return a request for comment by the time of publication.

In 2024, the California-based company recalled multiple mushroom-infused products, including chocolates, after they were found to contain higher-than-normal levels of the psychoactive compound muscimol.

“Muscimol could be a potential cause of symptoms consistent with those observed in persons who became ill after eating Diamond Shruumz products,” the Food and Drug Administration said at the time.

Researchers with the FDA, CDC, the Arizona Department of Health Services, and other institutions said in the new study that they investigated the outbreak and learned that it led to 180 reported illnesses with moderate or major symptoms among people who consumed from Jan. 1, 2024, through Oct. 11, 2024, a mushroom-containing item such as chocolate bars and gummies produced by Diamond Schruumz or another company.

Producers other than Diamond Schruumz were not identified in the report.

Two-thirds of the cases involved Diamond Schruumz products. The cases involving those products were significantly more likely to result in seizures, hospital admission, and intubation.

Nearly all cases, regardless of the product, prompted medical care.

Common symptoms included confusion, drowsiness, and agitation, with about three in 10 patients suffering from seizures. Symptoms typically appeared shortly after consumption, or from 30 to 180 minutes afterward.

Demographic information, available for most cases, showed that about half occurred among adults aged 18 to 29, and that a majority of patients were male.

Testing by federal and state officials identified chemicals found in psychoactive mushrooms in Diamond Schruumz products, as well as chemicals from the kava plant, a synthetic hallucinogen, and a pharmaceutical.

“Because the products and patient symptoms varied widely, the exact pathway leading to severe illness in these cases remains unclear,” the researchers said.

Limitations of the research included a likely underestimate of poisonings because certain people, the researchers said, might be reluctant to report eating the mushroom-containing products.

Funding sources were not listed. Authors disclosed no potential conflicts of interest, the CDC said.