In private Facebook groups devoted to natural treatments for cancer and other ailments, hundreds of thousands of members tell each other that baking soda, apple cider vinegar, and frankincense are cures doctors don't want you to know about.
Parents of children with autism have their own groups devoted to unscientific treatments — like swallowing bleach — that they believe will "heal" their children.
Facebook yesterday announced that it was taking steps to limit the reach of these false and sometimes dangerous claims by treating them as similar to clickbait or spam.
The announcement was the latest move by Facebook, which along with Google has recently started taking more aggressive action against medical misinformation on their platforms, where it thrived for years.
Facebook will "down-rank" posts it believes contain health misinformation, meaning those posts will appear in the news feeds of fewer users, and less prominently.