The author discusses the finding of blood on rock paintings from two sites in Australia (Laurie Creek, Northern Territory, and Judds Cavern, Tasmania) and the dating of the paintings through accelerator mass spectrometry (AMS) to obtain the radiocarbon dates of 20,000 years for the former and between 10,000 and 11,000 years for the latter site. Discusses the evidence for the use of human blood in ritual ceremonies in modern times and the development of this evidence to the use of the same material in the preparation of rock paintings. The use of immunological detection techniques pioneered by Thomas Loy are reviewed, as is archaeological evidence for the age of occupation of Tasmanian and mainland sites.