Hi Caroline. I am glad I have the opportunity to respond to this comment even if it is very late… The city air that you breath has more chance of causing you cancer than yerba mate. Over 200 million South Americans drink yerba mate every day, and cancer rates are relatively low in countries where yerba mate is consumed daily. In fact it’s Europe and the US that have the highest cancer rate per capita ( https://www.theguardian.com/news/datablog/2011/jan/24/worldwide-cancer-rates-uk-rate-drops ). It’s unfortunate that when one googles something which is truly nourishing and healthy that bogus articles pop up suggesting yerba mate causes cancer. None of these studies have been conclusive, none used clinical methodologies and none were independent. Try google “beer” or “vodka” and you will not find anything suggesting it may cause cancer on the first pages of search results.