A batch of bad of synthetic marijuana, also known as Spice, sent at least nine people to hospitals in Alachua County over the weekend.
Officials say the overdoses began Sunday and continued on Monday (Memorial Day).
The patients' admitted to the hospital due to the tainted Spice ages ranged from late teens to about 70.
Paul Myers, who oversees health agencies for the state, says the outbreak appears to be associated with some homeless people in the Gainesville area.
Effects of synthetic marijuana can include agitation, extreme nervousness, nausea, vomiting, diarrhea, a racing heartbeat, hallucination and dilated pupils.
Officials say they do not know where the individuals got the drugs, and do not know where the bad batch of synthetic marijuana was distributed.