In 1987, the FDA made azidothymidine — also known as zidovudine and usually shortened to "AZT" — the first government-approved treatment against HIV and AIDS. AZT is an antiretroviral which slows the replication of HIV, although it cannot stop it all together.
In the film, Dallas Mercy Hospital is having a randomized controlled trial to test AZT's effectiveness. Unable to be sure he's getting the drug rather than a placebo in the trial, Woodroof bribes a hospital employee to supply him with AZT, to which he reacts very badly. Throughout the rest of the movie, he and other characters denounce the drug as "toxic," and Woodroof recommends that customers of the buyers club dispose of what AZT they have and never take it again. At one point, a news broadcast is heard which emphasizes that AZT was the most expensive drug ever produced at that point. One could be forgiven for coming away with the sense that the medical community was poisoning HIV/AIDS patients with the drug, and keeping them from other, safer, therapies.
The trouble is that AZT is actually a very effective therapy against HIV/AIDS. "People who were consistently using AZT prolonged life for one year," says Jonathan Engel, a medical historian at Baruch College and author of "The Epidemic: A History of AIDS."That may not sound like a lot, but at a time when the disease had a mortality rate of 100 percent, anything that delayed death was valuable.]