Almost two million patients were back in A&E last year within a week of being sent home, figures show.
One in 12 admissions, over 8%, are return visits, the highest rate since records began six years ago.
There were 1.7million cases of people on unplanned A&E returns in England in the year to January.
NHS guidelines suggest a high rate of return trips is likely to reflect poor quality care and say re-attendance rates should be between 1% and 5%.
Harry is 'going along' with Meghan Markle but Queen may have reservations, says expert
The rise has been blamed on the social care crisis, with frail patients discharged without help at home.
Dr Taj Hassan, president of the Royal College of Emergency Medicine, said: “The number of hospital beds and community beds has decreased, which has led to reduced capacity.”
