Havana (CNN) -- Seven people have died after drinking poisonous alcohol in Cuba, and dozens more are hospitalized, state media reported Wednesday.
Tests showed the victims had been drinking toxic methyl alcohol, commonly found in varnishes and antifreeze, Cuban state media said.
More than 40 people remain hospitalized, the state-run Cubadebate website reported, eight of whom are in serious condition.
Victims began showing up at a Havana clinic Monday night with symptoms of poisoning, including nausea, headaches, vomiting, weakness and vision problems, state media said.
Authorities are investigating to determine who is responsible, Cubadebate said.
CNN's Catherine E. Shoichet contributed to this report.