Nepal, Nov. 14 -- Two small brown mushrooms can look almost identical. One may contain psilocybin, a psychedelic compound now in late-stage clinical trials for treatment-resistant depression. The other may carry toxins that destroy the liver and even cause death. Telling them apart takes training, not a photograph on social media.

That distinction captures Nepal's problem. Experts estimate that more than 30 Nepalis die each year after eating wild mushrooms, though no agency keeps an official count. Psychedelic mushrooms now add a new concern. A foreign drug-information site has billed Nepal as "Asia's top psychedelic tourist destination", and a mushroom website calls these fungi "not illegal yet". What happens when shops selling them ope...