The women are thought to have eaten poisonous death cap mushrooms
It could be up to three months before the results of toxicology tests are known on a woman who died after eating wild mushrooms, police have said.
The woman, in her 40s, was found dead at a house in Carisbrooke High Street, Newport, Isle of Wight, on Tuesday.
Another woman in her 20s, who told police they had picked and eaten death cap mushrooms, has been transferred to Kings College Hospital in London.
An inquest into the death is due to begin later.
The surviving woman told police she and her husband visited the 22-acre Ventnor Botanic Gardens, where they picked a number wild mushrooms, on Sunday.
The mushrooms were eaten by both women on Monday.
A Hampshire and Isle of Wight police spokesman said officers had shown a poisonous death cap fungus to the woman and she had said she had eaten that variety.
Police have not confirmed death caps were the cause of the death but are concerned there is a link and tests are taking place.
The victim, who has not been identified, was pronounced dead at her home address in Carisbrooke High Street after officers were called at 0712 BST.
An hour later, police were called to an address in Gunville Road, Newport, when they attended to the second woman and recovered a quantity of wild mushrooms.
Death caps are common throughout the UK and they contain a poison which attacks the liver and kidneys, if they are eaten.