If you are going to consider a study to be flawed because it uses rats, then you have to apply that to a hell of a lot of studies into your beloved pharmeceuticals & cosmecueticals.
And one of the biggest flaws in studies that decide chemicals are safe is that they don't study them long enough or study the cumulative affects of the massive amount of chemicals we come in contact with today.
Also, a hell of a lot of things are lumped into alternative medicine. So yeah.
Yes, rat studies are extremely common. Rat studies are used as a jumping board, not solid, irrefutable evidence that it does the same in humans. One shouldn't imply or claim that results from a rat study would be the same in people, especially all the time. One should also know how to interpret the results, as well as look into the study's quality.
Investigators determine whether a chemical is safe by looking at its bioavailiability, how it could accumulate, and what the chemical be used for and it what dosages. Inhaling vs. ingesting vs. topically applying the chemical makes all the difference between dangerous and safe. Again, you must look at study quality.
True, there are some treatments called "alternative medicine" because of how the surveys worded it.