Enlarge / A Diamond Shruumz chocolate bar, which comes in a variety of flavors. (credit: diamondshruumz.com)

The US Food and Drug Administration has identified a synthetic psychedelic compound as well as compounds from a potentially toxic plant in the Diamond Shruumz-brand microdosing candies linked to a growing number of severe illnesses nationwide that have included seizures, intubation, and admissions to intensive care units.

As of June 25, the case total has grown to 39, including 23 hospitalizations, across 20 states, the FDA and the Centers for Disease Control and Prevention reported.

It remains unclear what is in the candies and what may be causing the severe illnesses. Diamond Shruumz does not provide a full list of ingredients. The term "microdosing" and other marketing used by Diamond Shruumz suggests the candies contain a psychedelic compound, but the company does not name any. To figure it out, the FDA has been analyzing multiple samples of Diamond Shruumz-brand candies, including chocolates, gummies, and candy cones. On Tuesday, the FDA reported finding the synthetic psychedelic compound 4-AcO-DMT in the company's Dark Chocolate Bar and its Birthday Cake Chocolate Bar.