--- description: Two Americans have been treated with this experimental serum, but what exactly is it, and what does it do? title: What we know about the ‘secret’ Ebola serum image: https://static.time.com/v3/assets/bltea6093859af6183b/blt32c35d98b22707e7/69869e5e810bbb02d8c92e22/89001431.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  * [Health](/section/health/) ## Health Update your preferences in [Account Settings](/account/preferences/) Close * [Infectious Disease](/tag/infectious-disease/) ## Infectious Disease Update your preferences in [Account Settings](/account/preferences/) Close # What We Know About the ‘Secret’ Ebola Serum by [TIME Video](/author/time-video/) ## TIME Video Update your preferences in [Account Settings](/account/preferences/) Close Aug 5, 2014 5:32 PM CUT  Colorized transmission electron micrograph of the Ebola virus. Colorized transmission electron micrograph of the Ebola virus.Getty Images by [TIME Video](/author/time-video/) ## TIME Video Update your preferences in [Account Settings](/account/preferences/) Close Aug 5, 2014 5:32 PM CUT The two Americans infected with the Ebola virus, [Kent Brantly](http://time.com/3075848/cdc-ebola-patient-improving/ "undefined") and [Nancy Writebol](http://time.com/3082619/ebola-atlanta-american-nancy-writebol/ "undefined"), have received a dose of the experimental [Ebola](http://time.com/3079466/nigeria-second-ebola-victim/ "undefined") serum with encouraging results. The serum, however, has not been approved by the FDA or even tested on humans. The drug, called Z-Mapp, was developed by Mapp Biopharmaceuticals. It is one of the first treatments to show promise fighting the disease, and it works by preventing the [Ebola virus](http://time.com/3056038/ebola-virus-outbreak-explained/ "undefined") from infecting new cells. Though it’s ostensibly illegal to administer an untested drug, this situation would likely fall under the FDA’s “compassionate use” exception to treat patients with immediately life-threatening conditions. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/3082891/ebola-outbreak-serum/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/3082891/ebola-outbreak-serum/"},"headline":"What We Know About the ‘Secret’ Ebola Serum","datePublished":"2014-08-05T17:32:41.000Z","dateModified":"2026-02-21T09:30:38.583Z","description":"Two Americans have been treated with this experimental serum, but what exactly is it, and what does it do?","url":"https://time.com/3082891/ebola-outbreak-serum/","keywords":["Infectious Disease","U.S.","ebola","Liberia","Ebola outbreak"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/blt32c35d98b22707e7/69869e5e810bbb02d8c92e22/89001431.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"TIME Video","jobTitle":null,"url":"https://time.com/author/time-video/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/blt32c35d98b22707e7/69869e5e810bbb02d8c92e22/89001431.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"89001431","caption":"89001431","creditText":"Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/infectious-disease/","name":"Infectious Disease"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/3082891/ebola-outbreak-serum/","name":"What We Know About the ‘Secret’ Ebola Serum"}}]}] ```