In the late 19th century, one Clark Stanley begun marketing his Snake Oil as a cure-all. Made from the oils released by boiling rattlesnake, it made him a lof of money.
Unfortuantely his produce was found to be mainly mineral oil, and ineffective, and "snake oil" became a by-word for a fraudulent health product.
Selling bogus products is illegal and unethical and a scam. Do not be tempted!
Ironically, the health benefits of fish oil containing omega-3 fatty acid is well known, it just won't cure everything.