Three women collapsed and another injured her hand during the sales at branches of the fashion store Next.
Ambulance staff were "surprised" to be called to the same firm
Two of the women were taken to hospital suffering from suspected hypothermia after waiting for the store to open at Birmingham's Bullring.
A shop assistant had breathing problems at a store in Wednesbury, West Midlands, and a woman hurt her hand at Next in Fort Dunlop, Birmingham.
The stores, offering up to 50% discounts, opened as early as 0500 GMT.
A West Midlands Ambulance Service spokesman said: "Our staff were somewhat surprised to get so many calls to different branches of the same clothing company.
"If you are planning to attend and queue in the future, please ensure you wear suitable clothing to keep warm.
"Either have something to eat and drink before going or take it with you so that you don't become dehydrated or hungry."
The first call was to a 31-year-old woman who passed out at about 0425 GMT outside the Bullring's store. She was taken to City Hospital and missed the opening.
Another woman fainted at the store at about 0730 GMT and went to the same hospital. A hospital spokesman said two shoppers had suspected hypothermia.
The shop assistant in her 20s was taken ill a few minutes earlier at the branch in Wednesbury near the M6. She was taken to Walsall Manor Hospital.
A woman in her 20s suffered a hand injury at the Fort Shopping Centre in Birmingham and was treated at the scene.
No-one from Next was available for comment.