Cream was born in Glasgow in 1850, raised in Canada, and qualified in medicine at McGill in 1876, with further training in London and Edinburgh. He performed illegal abortions and was connected with several deaths in Canada before leaving for the United States.
In 1881, in Chicago, he poisoned Daniel Stott, an elderly man whose young wife was Cream's mistress, with strychnine supplied as an epilepsy remedy. The death would have passed as natural had Cream not written to the coroner insisting the chemist had made an error and demanding an exhumation. The letter is what convicted him. He was sentenced to life imprisonment in Illinois in November 1881 and released in 1891 after ten years, the sentence commuted.
He came to London and took lodgings in Lambeth. Between October 1891 and April 1892 he poisoned four young women working as prostitutes with strychnine in capsules he gave them as medicine: Ellen Donworth, nineteen; Matilda Clover, twenty-seven; and Alice Marsh, twenty-one, and Emma Shrivell, eighteen, who died together. Strychnine produces convulsions and a conscious, prolonged death.
As in Chicago, he wrote letters. He accused a physician of the killings, tried to extort money from another, and offered his services as an informant to the police, and it was that correspondence, not the medical evidence, that identified him. He was arrested on June 3, 1892.
He was tried at the Old Bailey in October 1892, convicted of the murder of Matilda Clover, and hanged at Newgate on November 15, 1892 by James Billington.
He is often called the Lambeth Poisoner. The claim that he confessed on the scaffold to being Jack the Ripper is a later invention and is impossible on the record: he was in an Illinois prison in 1888. It appears in popular writing and should not be repeated.