Mateu Orfila, who came from the island of Minorca and went on to fame in Paris, is generally credited with creating the science and practice of toxicology; the investigation of poisons and their nature, effects and their detection. His (1815) Traité des poisons became Europe’s textbook on the subject. But it was a science in the making, and everything about it was controversial. José Bertomeu-Sánchez explores Orfila’s use of live animals for testing poisons and antidotes, and his employment in legal trials as a toxicologist, especially for the detection of arsenic in cases of alleged poisoning. Orfila was a showman as well as an investigative scientist, and Bertomeu-Sánchez highlights Orfila’s public performances in front of students, fellow medical men and in the law courts, as well as his extensive chemical experiments. The developing situation was in no way clear-cut, as is shown by the continued controversy over the existence of ‘normal arsenic’ in the human body.