Residents of 12 villages in the South 24 Parganas district fell ill after drinking the alcohol. Four people have been arrested.
Some 100 other people are being treated in hospital, with fears the death toll could rise. Many died at home, fearing police would take action against them.
Toxic alcohol deaths are a regular occurrence in India.
Last week, the state of Gujarat brought in a new law making the illegal manufacture and sale of toxic alcohol there punishable by death.
The villagers drank the locally brewed alcohol on Tuesday evening and despite falling ill many stayed at home fearing police harassment if they went to hospital, reports the BBC’s Amitabha Bhattasali in Calcutta.
About 70 people are in a critical condition, state government minister Shyamal Mandal told the BBC.
Local officials said some hospitals were now overcrowded.
Local NGO workers told the BBC the liquor becomes toxic when it is spiked with ammonium nitrate to “add flavour”.
The illegal alcohol – commonly called desi daroo or country-made liquor in India – usually costs as little as 10 rupees (20 US cents) and the majority of the consumers are poor, daily-wage workers.
Gujarat has taken the strongest action on toxic liquor with its new law which, it says, is intended to deter those involved in the illegal trade.
Gujarat, Mizoram and Nagaland are the only states in India where alcohol is totally prohibited by law