Heimlich maneuver, also known as abdominal thrusts or Heimlich manoeuvre, is a first-aid procedure used to treat upper-airway obstructions (or choking) by foreign objects. American doctor Henry Heimlich is often credited for its discovery. To perform a Heimlich maneuver, a rescuer stands behind a choking victim and uses their hands to apply pressure to the bottom of the victim's diaphragm. This compresses the lungs and exerts pressure on the object lodged in the trachea in an effort to expel it.

Most modern protocols, including those of the American Heart Association, American Red Cross, and European Resuscitation Council, recommend that treatment of airway obstructions be performed in several stages designed to apply increasing levels of pressure. Most protocols recommend encouraging the victim to cough, followed by hard back slaps, and finally abdominal thrusts or chest thrusts as a final resort. Some guidelines also recommend alternating between abdominal thrusts and back slaps.

Thoracic surgeon and medical researcher Henry Heimlich, noted for promulgating abdominal thrusts, claimed that back slaps were proven to cause death by lodging foreign objects into the windpipe. A 1982 Yale study by Day, DuBois, and Crelin that persuaded the American Heart Association to stop recommending back blows for dealing with choking was partially funded by Heimlich's own foundation. According to Dr. Roger White of the Mayo Clinic and American Heart Association (AHA), “There was never any science here. Heimlich overpowered science all along the way with his slick tactics and intimidation, and everyone, including us at the AHA, caved in.”

Henry Heimlich also promoted abdominal thrusts as a treatment for drowning and asthma attacks. The Red Cross now contests those claims. The Heimlich Institute has stopped advocating on their website for the Heimlich maneuver to be used as a first aid measure for drowning victims. Heimlich's son, Peter M. Heimlich, alleges that in August 1974 his father published the first of a series of fraudulent case reports in order to promote the use of abdominal thrusts for near-drowning rescue. The 2005 drowning rescue guidelines of the American Heart Association did not include citations of Heimlich's work, and warned against the use of the Heimlich maneuver for drowning rescue as unproven and dangerous, due to its risk of vomiting leading to aspiration.

In May 2016, Henry Heimlich, then age 96, claimed to have personally used the maneuver to save the life of a fellow resident at his retirement home in Cincinnati. It was alleged to be either the first or second time Heimlich himself used his namesake maneuver to save the life of someone in a non-simulated choking situation. According to Heimlich's son, Peter M. Heimlich, "both 'rescues' were bogus."

A choking victim is usually unable to speak, and may not be able to make much sound. A universal sign of choking has been designated as a silent indication from a person who is unable to breathe, and consists of placing both hands on one's own throat while trying to attract the attention of others who might help.

Both the American Red Cross and UK National Health Service (NHS) advise that for a first attempt, a rescuer should encourage the patient to expel the obstruction by coughing. As a second measure, the rescuer should deliver five slaps to the back after bending the patient forward. Abdominal thrusts are recommended only if these methods fail.

The American Red Cross, the NHS, the European Resuscitation Council and the Mayo Clinic recommend a repeating cycle of five back slaps and five abdominal thrusts. They are not recommended on children below the age of one. In contrast to the prevailing American and European advice, the Australian Resuscitation Council recommends chest thrusts instead of abdominal thrusts.