Besides being crucial in emergencies, knowing your blood type could play a role in managing long-term health conditions—particularly cancer, according to some experts.
There are four main blood groups: A, B, AB, and O. Each can be positive or negative, depending on the Rh factor. “Interestingly, this isn’t something an NHS staff member will typically inform you about when taking your blood,” and many people only learn their type during specific medical treatments.

Research has explored whether certain blood types influence disease risk. A 2015 study suggested that only one of the four types was linked to a lower risk of certain cancers. Which one? Type O.

“Type O blood was associated with a lower likelihood of being diagnosed with stomach cancer,” the study found. People with Types A, B, and AB had a higher risk of stomach and pancreatic cancers. Dr. Sanjay Aggarwal noted, “It may be more accurate to say people with type O blood are at a lower risk for pancreatic cancer, given the work researchers are doing on bacterial infection.”Additionally, Type O blood has been linked to a reduced risk of colorectal cancer. However, no significant link was found between blood type and cancer survival rates.