Catherine Wilson was born around 1822 in Boston, Lincolnshire, England. Little is known about her early life, but she eventually moved to London and worked as a nurse and housekeeper. She married a man named Dixon, who later died under suspicious circumstances; a bottle of colchicum, a toxic substance, was found in his room. Although a doctor recommended an autopsy, Wilson pleaded against it, and the procedure was not performed.

Between 1854 and 1862, Wilson exploited her position as a nurse to poison several patients, encouraging them to leave their estates to her in their wills. Her preferred method was administering colchicum, a substance used to treat gout but lethal in large doses. In 1862, she attempted to poison Sarah Carnell with a "soothing draught" containing sulfuric acid. Carnell spat out the liquid, which burned holes in the bedclothes. Wilson fled but was arrested days later.

Initially tried for the attempted murder of Carnell, Wilson was acquitted after her defense argued that a pharmacist had mistakenly provided the acid. However, investigations into her past led to the exhumation of several former patients, revealing traces of poison. She was subsequently tried for the 1856 murder of Maria Soames, found guilty, and sentenced to death.

On October 20, 1862, Wilson was hanged outside Newgate Prison before a crowd of 20,000, becoming the last woman publicly executed in London. Despite her conviction for only one murder, she was suspected of killing up to seven individuals. Her case remains one of the most notorious examples of a healthcare professional exploiting their position to commit serial murder.