Lentaigne, Benjamin (1773–1813), physician, was born 14 February 1773 in Caen, Normandy, France, third son of Pierre François Lentaigne, lieutenant of dragoons, and his wife Anne Marguerite, daughter of Guillaume François Duclos. His family had strong royalist sympathies, one of his brothers serving with the Garde du Corps, and he was imprisoned following the outbreak of the French revolution. He eventually managed to escape (1789) to Flanders, where he joined the army of the emigrant princes before fleeing to England in 1792. His two elder brothers, Jean François and Joseph Lentaigne, were both guillotined in 1793. He studied surgery 1792–7 and was appointed as an assistant surgeon in the 5th Dragoon Guards in May 1797.
In 1798 he was stationed with his regiment in Ireland and, with H. Fitzpatrick, a Dublin physician, attended Theobald Wolfe Tone (qv) after Tone's suicide attempt of Sunday 11 November. He attended Tone on the morning of his death (19 November), warning him that any sudden movement would be fatal. Tone reportedly described this warning as ‘welcome news’ and, moving his head suddenly, caused a further haemorrhage that resulted in his death. Lentaigne later communicated his version of these events to a relative of Richard R. Madden (qv), historian of the United Irishmen. In August 1799 he resigned from the army and founded a medical practice in Dublin, based in Dominick St. Graduating from a Scottish university in 1800, he later graduated from TCD (1807) while also becoming a licentiate of the RCPI (1807). In 1813 he was awarded an honorary doctorate of medicine from TCD. He was a popular figure in Dublin and devoted two hours every day to providing a medical surgery for the poor of the city, a service he provided without any charge. Lentaigne also published a poem in Latin, De causis morborum. Apart from his Dublin practice and residence he also had a country home at Corlatt, Co. Monaghan. In October 1813 he contracted typhus fever, caught while attending a poor family, and died 13 October 1813.
He married (24 July 1799) Marie Thérèse, daughter and heiress of John O'Neill (d. 1803), a wealthy tradesman of Churchtown, Co. Dublin, who represented Athboy at the Catholic Convention of 1792. They had three sons and one daughter, including Sir John Francis Lentaigne (qv), inspector-general of prisons 1854–77.