Taranjebin Manna, a rare specific gum exudate from Fabaceae genera (Alhagi), screened for selenium content.These were from some 90 samples complied into 14 bulk samples, representing three regional centres of Iran.Previous multidisciplinary studies had suggested selenium in an exudate chemical species context was the likelyactive component. The present study supports this contention and explains Taranjebin Manna's very high ethno-medical demand in Iran, and for its export. Several proposed biochemical hypotheses introduced here supportselenium as the active constituent in context of Manna's glycoprotein content. Research into Manna selenopolysaccharides and selenoglycoproteins is likely to reveal novel compounds of high medical interest. It is arguedTaranjebin Manna ethno-medical indication for neonatal hyper-bilirubinemia and thyroid issues is related to theseselenium compounds. The mean content of selenium was consistently very high, averaging 492 mg Se/100 g (dryweight of Manna) in the range of 482 to 513 mg Se/100 g. As a result, important traditional medical Manna efficacyis inferred from these findings. Possible reason for this hyper-accumulation was investigated by conducting a reviewof selenium geogenic factors and Investigation into Taranjebin Manna’s distribution. This concluded biogeochemicalfactors such as specific local geogenic conditions combined with specific geological terrains contributed to Mannaselenium mobility within specific Alhagi genera species, Apersarum boiss, A. bushe and A. mannifera DesfClimatic,biological and geogenic-geological factors all contribute to high content of selenium in Taranjebin.