Not all products – cosmetic or otherwise – are tested on animals. However, in the US, this practice began in the early 1900s when product safety laws were introduced. This happened due to injuries and death resulting from products such as eyelash dyes and cough remedies.
Obviously, certain products cannot be tested on humans for safety reasons. If, for some reason, a product may have adverse effects on humans, some people think that it is better to put animals at risk. While this idea is controversial, especially for animal rights activists, the practice is still upheld by some manufacturers. Pressure from animal rights groups have lessened the practice of animal testing, though.