The hypothesis under examination in this research is that, as a consequence of illicit drugs being manufactured, 'cut', and distributed with no control over contamination, they are likely to contain traces of biological material such as microorganisms, plant remains, and other cellular material, all of which potentially contain DNA that could be used as a means to link apparently unrelated seizures or ascribe their provenance. In this research, non-human DNA in seizures was readily compared for similarities, pair-wise, seizure to seizure and this should be applicable to police intelligence almost immediately and court usage after considerable experience and validation. The technology's limits are explored and future developments are suggested. An additional unexpected finding was that a reasonable proportion of seizures yielded partial human DNA profiles upon extraction. Even in the relatively small quantities of drug subjected to testing, the human DNA content was sufficient for conventional forensic 'trace DNA' techniques to be quite promising. (Executive summary, edited)