With no proven drugs to treat Ebola and experimental ones in short supply, the health authorities are planning to turn instead to a treatment that is walking around in the outbreak zone in West Africa.

That would be the blood of people who have been sickened by the Ebola virus but have since recovered. Their blood should contain antibodies that might help other patients fight off the infection.

The World Health Organization is making it a priority to try such convalescent blood or plasma, as it is called, and is talking with the affected countries about how to do it.

This week, the organization issued guidance on how to collect the blood and administer transfusions.

“The concept that this treatment could be efficacious is biologically plausible, as convalescent plasma has been used successfully for the treatment of a variety of infectious agents,” the W.H.O. guidance document says.

Plausibility, however, is not proof that such treatments would work for Ebola and some virologists doubt it will. The results of studies in monkeys were discouraging, they note.

There will also be logistical problems carrying this out in West Africa, where blood banks are not well developed. One challenge will be to make sure that the donated blood, even if it helps patients recover from Ebola, does not give them H.I.V. or hepatitis.

“Major questions need to be answered about the safety and efficacy of convalescent therapies, and the feasibility of implementation in countries with shattered health systems and an acute shortage of medical staff,” the W.H.O. said in a separate statement released a week ago.

Still, with the epidemic spiraling out of control, there is a sense that some treatment needs to be offered, even if only to give sick people hope and a reason to go to medical centers, where they can be stopped from spreading the disease to others. And there are really no other good options.