&gt; Please point to the scientific research that states that psychedelics definitely do not affect your rectum.<p>Proving a negative isn&#x27;t typically the best scientific approach.  It&#x27;d be on the person making the dramatic claims to offer evidence.  There&#x27;s a lot of evidence about how cancer cells work and little (if any) gives reason to suspect some sort of conscious connection would affect it.<p>Though I think there is some data that people are more likely to recover if they feel more confident or at least not hopeless, but can&#x27;t remember where I read about that.  There was also something recently about an unexpected immune &#x27;tube&#x27; to the brain or something and I think there&#x27;s a positive correlation with being happy and getting sick less often.  All this is still a pretty far cry from claiming that psychedelics are likely to cure cancer.<p>Stating that the negative can&#x27;t be proven either does not make both arguments equivalent.