The use of a wide range of narcotic drugs in antiquity has been widely documented, although archaeologists have sometimes been too credulous of apparently scientific data, and have failed to appreciate the post-excavation histories of artefacts, including mummies. This paper examines the discovery of tobacco in the mummy of Rameses II, provides an alternative model for its origin, as a 19th-century insecticide used in conservation, and throws doubt upon the evidence for both cannabis and cocaine in ancient Egypt.