How Lethal Injection Works

By: Kevin Bonsor
lethal ingection
Syringe and toxic substance on this lethal injection. DavidHills / Getty Images

For thousands of years, many governments have punished people convicted of certain crimes by putting them to death, using various means to accomplish this. The death penalty is considered by many to be the ultimate form of punishment for those who have committed society's most heinous crimes, including rape and murder. As times have changed, so have the methods of execution.

The idea of someone being put to death is not a pleasant one. About 54 of the world's countries and 35 American states have a death penalty [source: Amnesty International]. The vast majority of executions in 2009 took place in China, Iran, Iraq and Saudi Arabia [source: Amnesty International].


The form by which prisoners are executed is changing. In America and a growing number of other countries, lethal injection has become the most commonly used form of capital punishment, replacing other forms such as hanging and the electric chair. In this article, we'll examine how lethal injection is carried out and what a prisoner experiences in the days prior to execution.


Condemned-inmate housing Adjustment Center at San Quentin State Prison
Photo courtesy California Department of Corrections

More than 3,175 men and women were serving death sentences in American prisons as of December 2009, according to the U.S. Department of Justice. Many of these people have been on death row for decades, waiting as their cases work their way through the appeals process. Some will die before ever having to face the execution chamber. Still, the number of executions taking place in the United States continues to grow.

Between 1977 and 1982, the years immediately following the reinstatement of the death penalty, there were a total of two executions. In 2004, there were 59 executions. An overwhelming number of these executions were carried out by lethal injection. On December 2, 2005, Kenneth Lee Boyd became the 1,000th person to be executed since 1977. In 2009, 25 people were executed in 11 states [source: Bureau of Justice Statistics].


The capital-punishment process begins when a person is convicted of a crime and sentenced to death. However, the execution can be delayed for years while the condemned prisoner makes his appeals to the courts. In the meantime, the prisoner lives in a section of a state or federal prison called death row. The specific events that follow can vary from state to state, but the overall process is generally the same.

Once a prisoner's appeals are exhausted, an execution order is given and a date is set for the execution. The condemned inmate may be moved from the general condemned housing area into a special area of the prison, called death watch. This area may be housed in the same building as the execution chamber. Some states move the inmate to another prison -- a central prison where executions are carried out.

Last 24 Hours

Just outside the death-watch cell at North Carolina's Central Prison. Some inmates are allowed to spend time in this area. Their last meal is served at this table.

In the final 24 hours before the execution, a prisoner can be visited by several people, including family, friends, attorneys and spiritual advisors. These visits take place in the death watch area or a special visitation room, and are halted sometime during that last day.

In the final few hours, several events take place in preparation for the execution. They do not necessarily occur in the order listed here and don't apply to every state:


  • Last meal is provided - Prisons try to provide whatever meal is requested by the condemned prisoner.
  • Warden and chaplain visit - The warden and the state-appointed chaplain visit with the inmate and stay until the end of the execution.
  • Witnesses arrive - There is no contact allowed between witnesses and the condemned prisoner. Witnesses are typically restricted to the witness room adjacent to the execution chamber, and are instructed to remain silent.
  • Inmate makes final preparations - In some states, male inmates are given a fresh pair of pants and a shirt, female inmates a dress, and the prisoner is allowed to shower before getting dressed. In other states, the inmate must remove all outer clothing.
  • Heart monitor is connected - The inmate is connected to an electrocardiogram (EKG) machine, which will be monitored for flat line to determine when the heart stops and death has occurred.

Once the inmate is dressed, he or she waits in the death-watch cell with a spiritual advisor until the warden gives the signal to bring the prisoner to the execution chamber. The prisoner is brought to the chamber just a few minutes before the scheduled execution.

Witnessing the Execution

Execution-witnessing area at San Quentin State Prison in California
Photo courtesy California Department of Corrections

Executions in the United States were once a public spectacle, and the tradition persisted well into the first half of the 20th century. According to the book "The Last Public Execution in America," by Perry T. Ryan, the final public execution performed in the United States was that of a man in Kentucky, who was publicly hanged in 1936. Thousands of people came from several states to gather around the gallows and watch the execution. In some states, admission was charged.

Some states began enacting laws prohibiting judicial public executions in the latter half of the 19th century. Today, executions are carried out behind prison walls with only a small group of witnesses in attendance.


Every state that performs executions has legislation providing for certain people to witness them. State laws vary as to who is allowed to watch an execution, but in general, these are the people who are allowed to be witnesses:

  • Relatives of the victim(s)
  • Relatives of the prisoner
  • Prison warden
  • Medical personnel
  • Spiritual advisor(s)
  • Prison guards
  • Official group of "reputable citizens"
  • Official group of state-selected witnesses
  • Media representatives
The witness room at Central Prison in Raleigh, N.C.

Witnesses may arrive anywhere from 20 minutes to two hours before the scheduled execution, at which point they are escorted by prison guards into the witness room. Relatives of the victim are sometimes placed in a different room than relatives of the prisoner, but not always. Some execution chambers have a one-way mirror that only allows the witnesses to see the condemned. Others have a clear window that allows the condemned to see the witnesses as well. Once the IVs are inserted into the prisoner's arms, the curtain covering the window is drawn back. Some states require complete silence in the witness area.

Once the execution is over, witnesses are escorted out by prison staff. Media and families may be taken to a press area for a press conference. The official witnesses sign a document attesting to the fact that they have witnessed the execution and that it took place.

Today, the closest we come to public executions is through the use of closed-circuit TV. In some cases, there are more relatives than the witness area can hold, so an overflow room may be set up in another room inside the prison that allows family witnesses to watch the execution via closed-circuit TV. In Illinois, family members can only view the execution through closed-circuit TV.

Inside the Chamber

Prisoners are strapped to this gurney in the preparation room just outside the execution chamber at North Carolina's Central Prison. Once IV tubes have been inserted into the prisoner's arms, the gurney is rolled into the chamber.

Few people know when there are only a few minutes left in their lives. Those sitting on death row are fully aware of when they are going to die, sometimes to the exact minute. Most state laws regarding capital punishment include a timeline of the events that must take place in the hours leading up to execution, including when the prisoner is to be taken to the execution chamber.

Once properly dressed, the inmate is taken to the execution chamber. They either walk on their own or are restrained to and rolled in on a gurney. Inmates who walk to the execution chamber are then restrained on a gurney or table either inside the chamber or in an adjacent preparation room. The inmate is secured to the gurney or table with lined ankle and wrist restraints. A sheet may be placed over the prisoner.


After the prisoner has been restrained, two intravenous (IV) tubes are inserted by the execution team, one tube in each arm. The intravenous tubes are threaded through an opening in the wall that leads to the anteroom, where the executioner is located. Once the IV tubes are inserted, a saline solution begins flowing into them.

The drugs are administered from inside this anteroom. Phones on the wall provide a connection to state officials who have the authority to stay the execution.
Photo courtesy California Department of Corrections

When the IV tubes are in place, a curtain may be drawn back from the window or one-way mirror to allow witnesses to view the execution. At this time, the inmate is given a chance to make a final statement, either written or verbal. This statement is recorded and later released to the media. The prisoner's head is left unrestrained -- in states that use regular windows, this enables the inmate to turn and look at the witnesses. In states that use one-way mirrors, the witnesses are shielded from view. In the next section, we'll talk about how the drugs are delivered to induce death.

Administering the Injections

Inside the execution chamber at North Carolina's Central Prison, where lethal injection is on hold because of the argument about whether a physician involved in the procedure breaks the Hippocratic oath

Unless a call is received from state officials to stay the execution, the execution proceeds as planned. While a lethal-injection machine exists, and was once used by several states, most states now opt to perform the injections manually due to the fear of mechanical failure. Usually an execution team comprises prison employees. Some states use the same personnel for every execution, while others rotate the duty among several employees.

The execution team is either in a separate room or behind a curtain and cannot be seen by witnesses or the condemned. In some cases, the executioners may wear a hood to conceal their identity. At the warden's signal, the execution team will begin injecting lethal doses of two or three drugs into the IVs. Some states use multiple executioners, all of whom inject drugs into an IV tube -- but only one of the executioners is actually delivering the lethal injection. None of the executioners know who has delivered the lethal dose and who has injected drugs into a dummy bag.


The drugs are administered, in this order:

  • Anesthetic - Sodium thiopental, which has the trademark name Pentothal, puts the inmate into a deep sleep. This drug is a barbiturate that induces general anesthesia when administered intravenously. It can reach effective clinical concentrations in the brain within 30 seconds, according to an Amnesty International report. For surgical operations, patients are given a dose of 100 to 150 milligrams over a period of 10 to 15 seconds. For executions, as many as 5 grams (5,000 mg) of Pentothal may be administered. This in itself is a lethal dose. It's believed by some that after this anesthetic is delivered, the inmate doesn't feel anything.
  • Saline solution flushes the intravenous line.
  • Paralyzing agent - Pancuronium bromide, also known as Pavulon, is a muscle relaxant that is given in a dose that stops breathing by paralyzing the diaphragm and lungs. Conventionally, this drug takes effect in one to three minutes after being injected. In many states, this drug is given in doses of up to 100 milligrams, a much higher dose than is used in surgical operations -- usually 40 to 100 micrograms per one kilogram of body weight. Other chemicals that can be used as a paralyzing agent include tubocurarine chloride and succinylcholine chloride.
  • Saline solution flushes the intravenous line.
  • Toxic agent (not used by all states) - Potassium chloride is given at a lethal dose in order to interrupt the electrical signaling essential to heart functions. This induces cardiac arrest.

Within a minute or two after the last drug is administered, a physician or medical technician declares the inmate dead. The amount of time between when the prisoner leaves the holding cell and when he or she is declared dead may be just 30 minutes. Death usually occurs anywhere from five to 18 minutes after the execution order is given. After the execution, the body is placed in a body bag and taken to medical examiner, who may perform an autopsy. It is then either claimed by the inmate's family or interred by the state.

Lethal Injection in the United States

Michael Henry and other protesters for Troy Davis gather on the steps of the Georgia Capitol building on Sept. 20, 2011, in Atlanta, Ga. Davis was executed by lethal injection on Sept. 21.
Photo by Jessica McGowan/Getty Images

Lethal injection is the world's newest method of execution, and is quickly becoming the most common one. In 1982, the United States became the first country to use lethal injection as a means of carrying out capital punishment.

Lethal injection was originally proposed as a means of execution in 1888 in New York, but the state chose electrocution instead. In 1977, Oklahoma became the first state to adopt lethal-injection legislation. Five years later, Texas performed the first execution by lethal injection.


Of the 38 U.S. states that have a death penalty, 34 use lethal injection as the primary form of execution. The U.S. federal government and the U.S. military also use lethal injection. In 2004, according to the U.S. Department of Justice, 59 people were executed in the United States, and all but one of those died by lethal injection. The number of states authorizing lethal injection increased from 27 in 1994 to 37 in 2004. In 2010, a shortage in one of the drugs used in lethal injection led to some states postponing executions.

U.S. executions were briefly halted in 1972 following the ruling of the U.S. Supreme Court on the case of Furman v. Georgia. The justices decided that executions were cruel and unusual punishment and therefore a violation of the Eighth Amendment of the U.S. Constitution. In 1976, the Court reversed this decision in the case of Gregg v. Georgia. To address the "cruel and usual punishment" objections, states began looking for a more humane way of carrying out the death penalty, lethal injection being one of the methods they came up with.

Lethal Injection Outside the United States

As of 2009, approximately 58 countries allow for some form of capital punishment [source: Amnesty International]. However, it should be noted that fewer than half of these countries are known to have performed an execution the same year. 

In 1997, China became the second country to use lethal injection to carry out an execution, 15 years after the first U.S. execution of this type. Three other countries, including Guatemala, the Philippines and Taiwan, also provide for execution by lethal injection.


Information about lethal-injection executions in China is hard to obtain, and the process by which they are carried out is unclear. Prior to 1997, China's main form of execution was shooting. According to a 1998 report from Amnesty International, the Chinese press reported 24 lethal-injection executions in that year, but the exact number is unknown.

While China was the first non-U.S. government to officially perform a lethal-injection execution, Taiwan was the first government outside of the United States to legislate lethal injection as a form of execution. However, Taiwan has yet to execute anyone by this method. Executions in Taiwan continue to be carried out by shooting.

In the Philippines, the death penalty was reinstated in 1993 after a six-year hiatus. The death penalty was brought back because of a rising crime rate. The country provides for the death penalty in cases of murder, rape, drug trafficking, kidnapping and arson, among other crimes. Under certain circumstances, the death penalty is a mandatory punishment.

In 1996, the Filipino government passed legislation allowing for executions by lethal injection. Soon after, a lethal-injection chamber was built at the National Penitentiary at Muntinlupa. The building consists of two, 60-foot metal cargo containers divided into five rooms. One room serves as the death chamber, and the other four are used by technicians, government officials, spiritual advisors and witnesses The Philippines performed its first lethal-injection execution in February 1999. It was the first Filipino execution since 1976.

Guatemalan law calls for the death penalty for those convicted of aggravated homicide of the country's president or vice president, killing a member of one's immediate family, killing a kidnap victim or raping a girl under the age of 10. A death sentence can be imposed only when all appeals have been exhausted. Guatemala carried out its first execution by lethal injection on February 10, 1998.

In Guatemala, once a death sentence is imposed, a judge selects a person to act as the executioner. On the day of the execution, much like in the United States, the prisoner is restrained to a gurney. In an adjacent room, the judge gives a signal to the executioner to begin. According to the law, an electronic lethal-injection machine is used to perform the injection of three drugs. Once the lethal injection has been administered, a forensic doctor examines the prisoner to declare the person dead. When the proceedings are over, the government either buries the body or turns it over to the person's family if they have requested to handle the burial themselves.

In October 2003, Thailand became the next country to adopt lethal injection as its main form of execution. Its first lethal injection executions were carried out in December 2003, when four men convicted of drug trafficking and murder were put to death.

Vietnam decided to replace the use of firing squads with lethal injection as its method of execution in 2010, with the decision taking effect in 2011.