Mária Gerzsány was born on March 25, 1851, in Kiskunmajsa. She came from a Catholic peasant family. During her early years, she lived in a time when there was no social security. This environment pushed her to work as a midwife, helping local women with childbirth. Over her career, she was involved in 95 births, but sadly, 78 of those babies were reported to have died. It was unclear if any of these deaths involved foul play.

Throughout her life, Mária was involved in various controversial activities. There were claims that she performed illegal abortions and was involved in trafficking young girls. Despite facing legal issues in multiple cases, she was never convicted of any crimes. At one point, she lived with a shoemaker named Antal Török on Szegedi Street in Kistelek, where she continued to advertise her midwife services.

Mária was married five times, and all of her marriages were described as tumultuous. Most of her ex-husbands died under strange circumstances. Mária had taken out life insurance policies on them, making her the sole beneficiary. In 1905, she moved in with a farmer named Ferenc Laczkó. Shortly after she took out a life insurance policy for him, he fell ill and died.

As her life continued, Mária's actions became increasingly suspect. She later admitted to creating and selling arsenic mixtures. Although many people had complaints about her, proving her involvement in any crimes was difficult. Surviving victims and their families often avoided cooperation with authorities, making investigations challenging. In an attempt to control her activities, law enforcement began imposing fines on her from 1909 to 1910.

In June 1911, Mária Gerzsány approached a woman named Mrs. Palinkás. She offered to provide arsenic to Mrs. Palinkás in exchange for 60 korona. Mrs. Palinkás, suspicious of Gerzsány, reported this offer to the police. The gendarmes were already watching Gerzsány for her previous suspicious activities. They gave Mrs. Palinkás marked money to use in the transaction. A few days later, Gerzsány suggested a stronger poison for an extra six korona. Again, Mrs. Palinkás told the police. On July 24, 1911, the authorities arrested Mária Gerzsány.

During the search of her home, the police found the marked money from the transaction. They also discovered many poisons, powders, and various tools that could be used for dangerous purposes. Following her arrest, the police began exhuming bodies from the local cemetery in Kistelek. Local villagers thought Gerzsány could have caused the deaths of over 50 people, but the police focused on exhuming six specific bodies. Among these were her two deceased husbands, as well as other victims. All the examined bodies showed signs of arsenic poisoning.

At her trial, several witnesses claimed that Gerzsány had offered them arsenic. Despite her denial and claims that the witnesses were lying out of vengeance, the evidence against her was compelling. As a result, she was sentenced to life in prison for murder and complicity in murder in 1912. One of her accomplices, Mrs. Sisák, was also convicted and received a 15-year sentence.

Gerzsány spent seven years in prison. She was ultimately released after the end of World War I, when Hungary faced significant changes. Upon her release, she returned to Kistelek, where rumors indicated she resumed her activities of selling arsenic. Some reports claimed she was hired by a woman wanting to poison her husband.

The police learned of these allegations and were concerned about Gerzsány's actions. They arrested her again on March 19, 1920. This time, she was sent to a different prison in Szeged to complete her life sentence. She died there from an unknown illness.