Ambroise Paré (French: [ɑ̃bʁwaz paʁe]; c. 1510 – 20 December 1590) was a French barber surgeon who served in that role for kings Henry II, Francis II, Charles IX and Henry III. He is considered one of the fathers of surgery and modern forensic pathology and a pioneer in surgical techniques and battlefield medicine, especially in the treatment of wounds. He was also an anatomist, invented several surgical instruments, and was a member of the Parisian barber surgeon guild.

In his personal notes about the care he delivered to Captain Rat, in the Piémont campaign (1537–1538), Paré wrote: Je le pansai, Dieu le guérit ("I bandaged him and God healed him"). This epitomises a philosophy that he used throughout his career. These words, inscribed on his statue in Laval, are reminiscent of the Latin adage medicus curat, natura sanat, "The physician cures, nature heals".

Paré was born in 1510 in Bourg-Hersent, later incorporated into Laval, then part of the province of Maine, in northwestern France. As a child he watched, and was first apprenticed to, his older brother, a barber-surgeon in Paris. He was also a pupil at Hôtel-Dieu, France's oldest hospital.

Paré was a keen observer and did not allow the beliefs of the day to supersede the evidence at hand. In his autobiographical book, Journeys in Diverse Places, Paré inadvertently practised the scientific method when he returned the following morning to a battlefield. He compared one group of patients who were treated in the traditional manner with boiling elder oil and cauterization, and the remainder with a recipe made of egg yolk, oil of roses and turpentine, and left overnight. Paré discovered that the soldiers treated with the boiling oil were in agony, whereas the ones treated with the ointment had recovered because of the antiseptic properties of turpentine. This proved this method's efficacy, and he avoided cauterization thereafter. However, treatments such as this were not widely used until many years later. He published his first book The method of curing wounds caused by arquebus and firearms in 1545.

Paré also reintroduced the ligature of arteries (first used by Galen and later described by Al-Zahrawi) instead of cauterization during amputation. The usual method of sealing wounds by searing with a red-hot iron often failed to arrest the bleeding and caused patients to die of shock. For the ligature technique he designed the "Bec de Corbeau" ("crow's beak"), a predecessor to modern haemostats. Although ligatures often spread infection, it was still an important breakthrough in surgical practice. Paré detailed the technique of using ligatures to prevent hemorrhaging during amputation in his 1564 book Treatise on Surgery. During his work with injured soldiers, Paré documented the pain experienced by amputees which they perceive as sensation in the 'phantom' amputated limb. Paré believed that phantom pains occur in the brain (the consensus of the medical community today) and not in remnants of the limb. He also performed many neurosurgical procedures.

In 1542, during the siege of Perpignan, Paré, accompanying the French army, employed a novel technique to aid in bullet extraction. During a battle, Maréchal de Brissac was wounded, having been shot in the shoulder. When finding the bullet seemed impossible, Paré had the idea to ask the victim to put himself in the exact position he was in when shot. The bullet was then found and removed by Henry's personal surgeon, Nicole Lavernault.

Paré was also an important figure in the progress of obstetrics in the middle of the 16th century. He revived the practice of podalic version, and showed how even in cases of head presentation, surgeons with this operation could often deliver the infant safely, instead of having to dismember the infant and extract the infant piece by piece. During his time at the Hôtel-Dieu, Paré directly influenced the education of future royal midwife Louise Boursier.

Paré also introduced the lancing of infants' gums using a lancet during teething, in the belief that teeth were failing to emerge from the gums due to lack of a pathway, and that this failure was a cause of death. This belief and practice persisted for centuries, with some exceptions, until towards the end of the nineteenth century lancing became increasingly controversial and was then abandoned.