A person who has diabetes can donate blood, according to the American Red Cross, as long as that person's diabetes is well-controlled on insulin or oral medication. However, a person with diabetes who has ever received bovine insulin made since the 1980's in the United Kingdom is not eligible.
These insulin users are not eligible because of risks associated with the transmission of Creutzfeld-Jacob Disease, or mad cow disease, according to the American Red Cross. A person must also be over the age of 17, depending on state laws, and weigh at least 110 pounds. A person wanting to donate blood must also feel well and be able to perform normal, everyday activities.