Propofol, the drug blamed on Friday for killing pop star Michael Jackson two months ago, is a fast-acting hospital sedative, administered intravenously and used as a precursor for anesthesia.
The drug, made by the pharmaceutical giant AstraZeneca, is also sold under the brand name of Diprivan.
On Friday, the Los Angeles coroner's office ruled that the pop icon's death was a homicide, revealing the singer had a lethal cocktail of six different drugs in his body when he died.
Ending several weeks of feverish speculation that has followed Jackson's sudden death in Los Angeles on June 25, the county coroner's office issued a brief statement ruling his death was unlawful.
The statement said that while "acute intoxication" from the powerful anesthetic propofol was the primary cause of death, Jackson, 50, had also suffered from the effects of other drugs in his system.
As well as propofol, powerful drugs including lorazepam, midazolam, diazepam, lidocaine and ephedrine were found in Jackson's body.
Los Angeles chief medical examiner-Coroner Lakshmanan Sathyavagiswaran "reviewed the preliminary toxicology results and his preliminary assessment of Jackson's cause of death was due to lethal levels of propofol."
Experts have warned that propofol is extremely powerful and not at all intended for use outside clinical settings.
"Propofol should have no business being in a house unless it happens to be equipped with an operating theatre," said Francois Chast, head of the pharmacology department at Paris's Hotel-Dieu Hospital.
The drug is administered either by intravenous drip or by injector ahead of anesthesia or to keep the patient anesthetised during an operation.
"Propofol is a preferred sedative in the operating theatre because it is well tolerated and enables patients to recover swiftly and well," said Chast.
"This is why it's commonly used in outpatient surgery or as a sedative for certain therapeutic or diagnostic examinations," such as endoscopies, he said.
Propofol is also used as a painkiller or anti-anxiety drug in post-operative care.
An overdose of Propofol can impede respiratory and cardiovascular function, leading to cardiac arrest, said Chast.
Friday's announcement will fuel speculation that authorities are likely to charge Jackson's personal physician Conrad Murray in connection with the death.
Murray, a cardiologist, was the last person to see Jackson alive and had over a long period of time administered propofol and other drugs to Jackson -- at the star's insistence -- to treat his insomnia.