Pipe residues suggest cannabis smoking in medieval Ethiopia

Two ceramic pipe bowls excavated in Lalibela Cave near Lake Tana became evidence for a much earlier history of cannabis smoking in Ethiopia. In a chapter published in Cannabis and Culture (1975), Nikolaas J. van der Merwe interpreted chemical traces in their residues as products of cannabis combustion.

The frequently repeated date, about 1320 CE, comes from an associated radiocarbon determination for the excavation layer. It was reported as 1320 ± 80 CE, not as a precise year when someone smoked a pipe.

Bowls from an archaeological layer

J. C. Dombrowski excavated the objects in the cave’s second level, in what was then Begemeder Province. Van der Merwe described both as parts of water pipes: an opening beneath each bowl could receive a stem descending towards a water container.

One bowl, designated B2, was well preserved and retained a substantial deposit. The other, A2, was broken and held much less residue. Their archaeological context preceded the introduction of American tobacco to Africa, making the identity of the smoked material an important question.

What the tests actually found

Van der Merwe used thin-layer chromatography, comparing extracts from the old residues with cannabis material and modern smoking pipes. The ancient samples did not produce the usual spots for THC, cannabinol or cannabidiol.

Instead, faint spots appeared at two other positions. Similar spots also appeared in modern cannabis-pipe residues. He interpreted them as unidentified, longer-lived cannabinoid degradation products formed through heating.

The preserved bowl gave two positive tests under that interpretation; the broken bowl gave one. A later attempt produced no detectable spots, and insufficient sample material prevented further testing. The chapter therefore records both a positive interpretation and the practical limits of its investigation.

Evidence and interpretation

The result is a historical chemical argument, not a modern direct measurement of THC. It is more accurate to say that the residues suggested cannabis smoking than that intact THC was discovered in fourteenth-century pipes.

The chapter does not identify the smokers, establish a religious ceremony or prove how cannabis reached the region. Van der Merwe proposed an Arabic connection as probable, while explicitly acknowledging that the route and timing were unknown.

The find belongs to the material history of cannabis in Ethiopia. It does not establish continuity with any modern religious community or explain the country’s later drug laws.^[1]