While looking for research articles, I came across this one done in Australia in 1973. www.ncbi.nlm.nih.gov/pmc/articles/PMC1776598/pdf/brjpharm00542-0029.pdf The effect of cannabinoids on intestinal motility and their antinociceptive effect in mice [PDF] They used a very complicated way to extract a "red oil" using petroleum and chloroform.