Mrs Allanson said she was left cold and wet at home on her own
The family of a widow from Leeds is demanding an apology after she was discharged from hospital in the middle of the night wearing just a nightgown.
Elsie Allanson, 74, was admitted to the city's St James's Hospital last month after suffering a suspected stroke.
She was sent home in a taxi in freezing weather at 0200 GMT the next day. Her family had not been informed.
Her daughter said the hospital should admit its mistake. The NHS trust said it would be "inappropriate to comment".
Mrs Allanson, who suffers from chronic chest problems and angina, was admitted to St James's with a suspected mini-stroke on 23 February.
The great-grandmother, who lives alone, was then sent home in a taxi in her nightgown and slippers in the early hours of 24 February - one of the coldest nights of the winter.
She was eventually re-admitted that afternoon and remained in hospital for another three days.
She said: "I feel a bit angry at being sent out in all that snow because if I had known they were going to do that I wouldn't have gone in the first place.
"I felt cold, I was wet, my dressing gown was wet, my slippers were wet because I had walked through the snow.
"The house was cold because the central heating had gone off."
Her daughter June Spencer said her mother was lucky because the taxi driver had carried her up an icy path into the house.
"If it hadn't been for a competent taxi driver she could have been dead in the garden," she said.
"I would like the hospital to turn round and say: 'We have made a mistake and we will make it our policy not to discharge vulnerable people in the middle of the night.'
"It's not just for my mother, it could be for anybody's mother."
A spokesperson for Leeds Teaching Hospitals NHS Trust said: "We are sorry to hear that Mrs Spencer has concerns about the care received by her mother.
"Mrs Spencer has been in touch with the matron and has already had informal discussions with her.
"We would advise Mrs Spencer to consider making a formal complaint to enable us to fully investigate the concerns she has.
"It would be inappropriate to comment further at this stage."