The NHS has made an urgent appeal for O Negative blood donors after the norovirus outbreak and the festive period caused a drop in donations.
The National Blood Service (NBS) said it had increased stocks of the blood type before Christmas but high demand meant it was running low.
More than one million people are believed to have been affected by the vomiting bug outbreak, which led several hospitals to close their doors before Christmas in a bid to contain its spread.
An NBS spokesman said: "Blood stocks can often dip around holiday time as people get distracted and can't always attend their sessions.
"In addition, the recent outbreak of norovirus has led to a dramatic increase in the number of people correctly cancelling their appointments. Non-attendance by O Negative donors increased by 50% just before New Year."
Donors with O Negative blood make up around 7% of the population and are known as the "universal donor" as their blood can safely be given to patients with a different blood group. This can prove vital in an emergency situation where there may not be time for an immediate blood group testing to be carried out.
About 100,000 people were struck down with the winter vomiting bug over Christmas according to the latest figures, with the number of confirmed cases 72% higher than this time last year.
The dramatic rise was attributed in part to an early outbreak of the illness which closed dozens of hospital wards as it swept across the country. During the two weeks up to December 30, there were 29 hospital outbreaks reported, compared with 70 in the previous fortnight, bringing the season's total to 590.
A total of 3,877 laboratory-confirmed cases of norovirus have now been recorded in England and Wales - up on the 2,255 of last year. But the Health Protection Agency (HPA) said that for every reported case, an estimated 288 were not flagged up, meaning about 1.12 million people could have contracted the illness this season.
Blood stocks are also needed for patients being treated for diseases such as cancer and leukaemia, with anyone aged 17 upward who is in generally good health a potential donor.