Snake oil originally was a Chinese medication rich in omega-3 fatty acids which was made from de Chinese water snake. It was believed to decrease the pain of arthritis. The Hopi medicine men had used rattlesnake oil as an anti-inflammatory. Rattlesnake oil has a lower concentration of omega-3 fatty acids. Towards the end of the 19th century Clark Stanley started selling rattlesnake oil as a cure for all diseases.The fact that this snake oil did not work led to the use of the term “snake oil” for substances of questionable efficacy that were sold with extravagant claims.
Morley, J.E. J Nutr Health Aging (2019) 23: 490.