And if it turns out that the drug you bought in Mexico was baking soda, you don't have any right to sue, gringo.   The US bears the price of the research and development and all the litigation costs, then the rest of the World that doesn't do the R&D and doesn't have the US' avaricious plaintiffs' bar gets the benefit.

You buy a drug in Mexico, you're buying from the guy who paid the last best bribe to the guy who prints the downloaded label.