The Iowa Department of Public Health says there have been 38 cases of vaping-related illnesses in the state since the summer. Of those, 33 involved involved individuals using illegal THC products.
THC is the ingredient in canbabis that causes a high.
"Youth should be discouraged from using vaping and e-cigarette products of any kind as the long-term health impacts for youth using these products are unknown," the health department says on its website.
The Centers for Disease Control says there are more than 1,300 cases nationwide.
Some states have attempted to ban flavored vapes and e-cigarettes, arguing the flavors appeal to young users. Michigan Gov. Gretchen Whitmer signed an executive order last month banning flavors for six months.
Opponents of such bans say the flavors have helped smokers quit smoking cigarettes.