It's worth noting the original "snake oil" from Chinese water snakes was high in omega 3, so it may have some minor medical effect[0][1]. The later marketing of rattlesnake oil and fakes made from mineral oil is where the term comes from.

[0] https://www.scientificamerican.com/article/snake-oil-salesme...

[1] https://pubmed.ncbi.nlm.nih.gov/17622788/