The advertising watchdog received a complaint about a direct mailing for Anthony Nolan’s bone marrow donor register, which included the words "Be a match, save a life". Text on the envelope said: "With your help we can double the number of lives we save."
The complainant had challenged whether the mailing misleadingly exaggerated the likelihood of transplants saving lives.
In its response, the charity said the number of transplants had increased dramatically over the past 30 years, which would not have happened if there was no evidence of survival or patient benefit.
However, for every patient it matched through the register, there was another it could not.
The ASA concluded that readers were likely to understand that transplant procedures might benefit patients with life-threatening conditions but were also potentially risky, subject to potential complications and would not guarantee the recipient’s life would be saved or prolonged.
Richard Davidson, director of communications at Anthony Nolan, said he welcomed the ASA’s decision.