Specifically, by removing cafestol: https://en.wikipedia.org/wiki/Cafestol https://en.wikipedia.org/wiki/Cafestol However, cafestol potentially also has benef

Specifically, by removing cafestol: https://en.wikipedia.org/wiki/Cafestol https://en.wikipedia.org/wiki/Cafestol However, cafestol potentially also has beneficial health effects, so it is not necessarily bad. I'm not aware of any study comparing health outcomes (as opposed to blood test results) of filtered vs. non-filtered coffee. This latest study does not distinguish between them.