Incidents of mass deaths from drinking cheap home-made alcohol substitutes are not uncommon in Russia, which has been blighted by high levels of alcoholism for years.
The regional government's press service said in a statement that "19 deaths after alcohol consumption were recorded in the Slantsy District in September."
It added that eight cases had so far been "laboratory-confirmed as methanol poisoning."
Investigators said they had detained a man and a woman after prosecutors opened a criminal case to probe "the poisoning of several residents of the Slantsy District with counterfeit alcohol."
Earlier this week, prosecutors sentenced two people to almost a decade in prison for manufacturing and selling a counterfeit cider drink that killed 50 people in 2023.
And in 2016, more than 60 people died in Irkutsk in Siberia after drinking contraband bath oil that contained methanol.
Russia toughened its legislation after that incident, but cheap home-made spirits using alcohol substitutes remain widely available, particularly in rural areas with low standards of living and where the price of vodka is prohibitively high, reports BSS.