Catherine Deshayes, later known as La Voisin, was born around 1640 in France. She married Antoine Monvoisin, a jeweler whose business ventures failed, leading to financial hardship. To support her family, Catherine turned to various occupations, including midwifery, fortune-telling, and the sale of potions and remedies. 

Her clientele ranged from commoners to members of the aristocracy, drawn to her for solutions to personal and professional problems. Over time, her services expanded to include more illicit activities, such as arranging black masses and providing poisons for those seeking to eliminate rivals or unwanted individuals.​

Between 1660 and 1679, La Voisin became a central figure in the infamous Affair of the Poisons, a major scandal during the reign of King Louis XIV. She led a network of fortune tellers and alchemists in Paris, offering services that included poisonings, love potions, and purported magical rituals. Clients from various social strata, including nobility, sought her assistance for personal gain or to remove obstacles. Her involvement in these activities led to suspicions of numerous deaths, although the exact number remains unknown.​

In 1679, authorities began investigating a series of mysterious deaths among the French aristocracy, leading to the exposure of La Voisin's network. She was arrested on 12 March 1679 and subjected to interrogation. Despite the use of torture, she denied practicing witchcraft but admitted to providing poisons. Her trial concluded in February 1680, resulting in her conviction for witchcraft and poisoning. On 22 February 1680, La Voisin was executed by burning in Paris, marking the end of her notorious career and serving as a cautionary tale during a period rife with fear of witchcraft and poisoning.​