Gummy bears that may have been laced with marijuana or marijuana oil made several west suburban students sick on Tuesday, but authorities still don’t know what they were laced with.

Students began visiting the Naperville North High School nurse feeling “uncomfortable and sick” after eating gummy bears that may have contained another substance, Naperville Community Unit School District 203 spokeswoman Michelle Fregoso said.

For safety precautions, 14 students were transported to Edward Hospital, where 12 were treated, she said. Each student experienced varying degrees of discomfort, including a fast heart rate, dizziness and dry mouth.

All of them have since been released from the hospital, police said.

Naperville police believe the gummy bears were distributed by another student, and while they think they contained marijuana, tests to determine the substance will take some time to complete.

The 17-year-old was taken into custody for questioning, but later released. Police were looking into multiple suspects in connection with the incident and said charges would be filed “once the case is finalized.”

“It would appear from our investigation that the candy was homemade and not store bought,” police said on Friday. “In addition, we still believe that it was a form of cannabis in the gummy bears that made the students ill, but we are awaiting lab results to confirm this.”

It was not known whether the students knew the candy was laced with another substance when they took it, but police and the school are urging parents to discuss the matter with their children.

“We urge parents to reinforce with their children the importance of only accepting unopened candy or other forms of food or drinks from individuals they know and trust,” police said.

The school district was also encouraging parents “to have conversations with their children about making healthy choices. Our community is fortunate to have a number of resources available through school and other community partners to support the well-being of students,” Fregoso said in a statement.