250 years after his death, Thomas Chatterton continues to create discussion amongst the literati and enchant the people of Bristol. The controversy of his life was entwinned with his writings where he passed his work off as that of a fictional medieval poet – Thomas Rowley. His premature death at the age of 17 in 1770 is also shrouded in controversy – did he commit suicide from arsenic poisoning (as stated at the original inquest into his death), or did he accidentally overdose on laudanum (as suggested by the 1947 forensic analysis)? The purpose of this study is to use state-of-art analytical methods (namely ultra-high-performance liquid chromatography tandem mass spectrometry using an Orbitrap mass spectrometer) to investigate the brown stain found on his memorandum book. The conclusion of this study is that that stain is made up of, amongst other things, 18 opiate and 1 opioid degradation product – 9 of which are previously unpublished, and that the spillage was indeed due to laudanum.