Five Lancaster University students have been admitted after taking a substance Police think is synthetics cannabis substitute.
The students had fallen ill after taking the synthetic cannabinoids, named Spice.
Lancaster University authorities took to Twitter to alert their students while campus police searched students' accommodations for the substance.
Three of the students were discharged with two still being treated in a "conscious but stable condition."
Lancashire police say they are collaborating with the university to "identify the exact nature of the substance, which at this stage appears to be some form of cannabis substitute."
BBC reports that synthetic cannabinoids are chemicals that act like the active part of cannabis, a substance called tetrahydrocannabinol (THC), with side effects that include elevated heart rate, sickness, and hallucinations.
Spice, one of the many synthetic cannabinoids available, has been banned in the United Kingdom for several years.