Twelve students were sent to the hospital after showing symptoms consistent with a drug overdose, the CBS affiliate WFSB reported.
Students allegedly overdosed on the drug MDMA, a variant of Ecstasy that is also known as "Molly," at a party on Saturday night at the Eclectic Society House, a coeducational group.
Multiple calls were placed to police, and police and Wesleyan continue to investigate the incident, although police are treating the MDMA used at the party as a "bad batch," WFSB reported.
Wesleyan President Michael Roth said the patients were 10 Wesleyan students and two visitors.
As of Monday evening, eight people were still in the hospital, and four were expected to be released late Monday. On Sunday evening, two patients had been in critical condition and two in serious condition.
MDMA was cited in the deaths of two attendees at the Electric Zoo music festival in 2013, and hospitals in 2011 reported more than 22,000 MDMA-related emergency room visits, WFSB reported.