Botanical identity of soma–haoma

There has been much speculation as to the botanical identity of soma or haoma. Soma is a plant described in Hindu sacred texts including the Rigveda, while haoma is a plant described in the Avesta, a collection of Zoroastrian writings. Both names are derived from the Proto-Indo-Iranian *Sauma.

Soma/Haoma is considered to be a concoction of multiple ingredients instead of one plant, however the primary botanical plant and active ingredient is debated. In the past 250 years scholars have tried to identify this, with proposed candidates including various species of plants and or fungi. Theories currently endorse that soma/haoma was either Ephedra, fly-agaric mushrooms, or Syrian rue. The leading scholarly consensus on the botanical identity of soma/haoma has been Ephedra (particularly Ephedra gerardiana, Ephedra intermedia, or Ephedra equisetina). Furthermore, Ephedra has historically been the most purported due to being called som/hom/hum in South and Central Asian languages. Ephedra geradiana in particular was called Somalata (moon plant) in Sanskrit.

Researchers also suggest other plants with and without psychoactive properties, such as the perennial Peganum harmala, Nelumbo nucifera (also known as the "sacred lotus"), Cannabis sativa, and the sugarcane species Tripidium bengalense (synonym Saccharum sara); while fungal candidates include the fly-agaric mushroom Amanita muscaria, the psilocybin-containing mushroom Psilocybe cubensis, and the ergot fungus Claviceps purpurea, Phalaris aquatica, and Datura metel. Soma/haoma has been described as being mixed with other substances (e.g. fermented mare's milk or fermented honey). Srauta Brahmins called Somayajis use Cynanchum acidum today.