Lifestyle · August 13, 2026 · The Conversation · 5 min
A painted panel deep in a Spanish cave may push the human relationship with mind-altering plants back thousands of years, earlier than anything previously known.
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<span><a href="https://theconversation.com/profiles/benjamin-pothier-2223669">Benjamin Pothier</a>, <em><a href="https://theconversation.com/institutions/university-of-plymouth-717">University of Plymouth</a></em></span>
<p>Deep in the El Castillo cave in northern Spain, up a side passage off the main pathway, there is a small painted panel most visitors would walk straight past. </p>
<p>Created some 17,000 to 15,000 years ago, it shows five red signs, each shaped a little like a bell. A natural stone ledge runs beneath them like the lip of an altar. For over a century, <a href="https://theconversation.com/topics/archaeology-695">archaeologists</a> have simply catalogued these as “bell-shaped signs”, filed under the vast heading of ice age marks we don’t know the meaning of.</p>
<p>Building on my <a href="https://pearl.plymouth.ac.uk/ada-theses/79/">PhD research</a> surveying plants used in <a href="https://theconversation.com/topics/shaman-70167">shamanic ritual</a> worldwide, I argue they may be flowers. Mind-altering flowers, to be specific – the bell of a psychoactive nightshade, most likely belladonna or a local henbane. </p>
<p>I published a paper in 2021 making a similar case for a tree drawn on the <a href="https://www.tandfonline.com/doi/full/10.1080/1751696X.2021.1865646">Chu Silk Manuscript</a>, China’s oldest illustrated text. I read this tree as a plant credited in early Chinese herbals with letting its user see and speak with spirits. </p>
<p>If my interpretation is correct, then these unremarkable red signs would be the oldest known picture of a mind-altering plant anywhere in the world, by thousands of years. And it could be corroborated the way it was at <a href="https://www.pnas.org/doi/full/10.1073/pnas.2014529117">Pinwheel Cave</a> in California, where chewed bits of hallucinogenic plant matter found wedged into the rock gave the first unambiguous physical proof anywhere in the world that a plant depicted in rock art had been ingested at the site.</p>
<p>Look at a belladonna flower and then at the signs, and the resemblance is hard to unsee: a drooping, five-lobed bell, its mouth flaring outward, with faint veins running down the corolla. </p>
<p>The El Castillo signs share this silhouette — the flared bell, the downward hang, and, on several, a central line echoing the vein of the living flower. Henbane, another psychoactive nightshade native to the region, produces a similarly shaped bell at certain stages of its growth.</p>
<figure class="align-center "> <img alt="Side by side: a belladonna (Atropa belladonna) flower and detail of the El Castillo bell signs." src="https://images.theconversation.com/files/752024/original/file-20260804-50-rrlkno.jpg?ixlib=rb-4.1.1&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/752024/original/file-20260804-50-rrlkno.jpg?ixlib=rb-4.1.1&q=45&auto=format&w=600&h=270&fit=crop&dpr=1 600w, https://images.theconversation.com/files/752024/original/file-20260804-50-rrlkno.jpg?ixlib=rb-4.1.1&q=30&auto=format&w=600&h=270&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/752024/original/file-20260804-50-rrlkno.jpg?ixlib=rb-4.1.1&q=15&auto=format&w=600&h=270&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/752024/original/file-20260804-50-rrlkno.jpg?ixlib=rb-4.1.1&q=45&auto=format&w=754&h=339&fit=crop&dpr=1 754w, https://images.theconversation.com/files/752024/original/file-20260804-50-rrlkno.jpg?ixlib=rb-4.1.1&q=30&auto=format&w=754&h=339&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/752024/original/file-20260804-50-rrlkno.jpg?ixlib=rb-4.1.1&q=15&auto=format&w=754&h=339&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"> <figcaption> <span class="caption">Side by side: a belladonna (Atropa belladonna) flower and detail of the El Castillo bell signs.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:IMG_8028_Atropa_belladonna_L._Single_flower_in_profile.jpg">Flower photo: Flobbadob on Wikimedia Commons | Cave painting photo courtesy of Geneviève Von Petzinger</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span> </figcaption> </figure>
<p>Some might argue that a bell is a simple form, and simple forms recur by chance. But what I feel lifts these signs above coincidence is the company they keep: the deliberate grouping, the altar-like ledge, and the weight of independent evidence that prehistoric Europeans knew these plants intimately.</p>
<p>Other readings exist. Following the French archaeologist André Leroi-Gourhan’s <a href="https://www.persee.fr/doc/bspf_0249-7638_1958_num_55_7_3675">mid-20th-century framework</a>, ovals, triangles and rounded forms across Palaeolithic sites like these bell-shaped signs were often catalogued as vulvar or female symbols. Some specialists, including Canadian paleoanthropologist <a href="https://uk.bookshop.org/a/15793/9781476785509">Genevieve von Petzinger</a>, have since pushed back on this once-dominant interpretive lens. They argue that it reflects the assumptions of the – largely male – early researchers, as much as the evidence itself. </p>
<h2>A plant Europe never forgot</h2>
<p>The nightshades are among the most written-about psychoactive plants in European history. Their active compounds – atropine, scopolamine, hyoscyamine – produce vivid hallucinations and the striking sensation that one’s skin is sprouting fur or feathers. </p>
<figure class="align-left zoomable"> <a aria-label="Zoomable image" href="https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=45&auto=format&w=1000&fit=clip"><img alt="A crude model of a lioness's head on a human body" src="https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=45&auto=format&w=754&h=1341&fit=crop&dpr=1 754w, https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=30&auto=format&w=754&h=1341&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/752057/original/file-20260804-60-3bilg0.jpg?ixlib=rb-4.1.1&q=15&auto=format&w=754&h=1341&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a> <figcaption> <span class="caption">The lion-man of Hohlenstein-Stadel.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Loewenmensch1.jpg">Dagmar Hollmann</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span> </figcaption> </figure>
<p>This has echoes of the part-human, part-animal figures common in ice age art, from the <a href="https://www.academia.edu/20285519/">lion-man of Hohlenstein-Stadel</a> – a 40,000-year-old ivory carving with a human body and the head of a cave lion – and the <a href="https://academicjournals.org/journal/IJSA/article-full-text-pdf/17D60B05901">“sorcerers”</a> of French caves, human figures fused with antlers, claws or a beast’s tail, long read as shamans caught mid-transformation.</p>
<p>There is also evidence that these plants were used in rituals by later Europeans. Chemical analysis of bronze age human hair from the burial cave of <a href="https://www.nature.com/articles/s41598-023-31064-2">Es Càrritx in Menorca</a> confirms people there consumed multiple psychoactive compounds, atropine and scopolamine among them, around 3,000 years ago. </p>
<p>Belladonna’s use threads through European history right up to the witch trials in Germany, France and Italy, roughly from the 15th to 17th centuries, where it was considered a staple of the “flying ointments” said to carry witches to the sabbath. The question this panel poses is how far back that thread runs.</p>
<p>The documented relationship between humans and mind-altering plants, in image form, essentially begins in the neolithic. The famous “mushroom” figures of <a href="https://www.akjournals.com/view/journals/2054/3/2/article-p43.xml">Tassili n'Ajjer in the Sahara</a> – a vast Algerian plateau of prehistoric art, where humanoid figures appear studded with mushroom-like shapes – have been read by some researchers as an early depiction of ritual mushroom use. The oldest widely discussed candidates date to roughly 7,000–9,000 years ago. </p>
<p>The El Castillo panel belongs, according to a <a href="https://dialnet.unirioja.es/servlet/articulo?codigo=8060381">chronological study of the cave’s iconographic stratigraphy</a> (overlapping layers of cave art), to the lower Magdalenian period – some 17,000 to 15,000 years ago, deep in the last ice age. That would push the picture back 7,000 to 10,000 years, into the upper Palaeolithic. </p>