The number of people in Russia who have died as a result of drinking bath oil has risen from 49 to at least 58, local media has reported.
Most of the 37 other people who became ill are still being treated, with some in a serious condition.
The highly toxic hawthorn-scented liquid was consumed as if it were safe alcohol, according to Russia's Investigative Committee.
But it contained poisonous methanol, which can also cause blindness.
The Siberian Times said the mass poisoning in Irkutsk "is now the worst such case in modern Russian history".
Health minister Oleg Yaroshenko said that almost half of those still being treated are not expected to live and were in a very serious condition.
"They came to [the] doctors too late.... Only a miracle can save them," he was quoted by The Siberian Times as saying.
The paper said that a doctor and a kindergarten teacher are among the victims and that many of those who died were discovered in their homes because they did not have sufficient time to call an ambulance.
Most of the victims are reported to be aged between 35 and 50.
One 33-year-old survivor said that he only drank a small amount of the lotion but still woke up blind the following morning.
Household products are seen by some as a cheap alternative to alcohol across the former Soviet Union.
Bottles with the lotion normally carry warnings stating they are not to be consumed, but correspondents say that the labels in this case said that the product contained ethyl alcohol rather than deadly methanol.
Analysts say up to 12 million Russians drink cheap surrogate alcohol, including perfume, after shave, anti-freeze and window cleaner. Two years of Western economic sanctions have made the situation worse.
Police earlier uncovered an illicit workshop where the lotion was being made, and arrested its owners.