You make a very good point - it can be dangerous if you don't know what you're doing. There are lots of pills and faux supplements out there that claim to detox, but are actually full of a bunch of crappy chemicals that make the effort pointless. Natural ways to detox like lemon water with cucumber, etc. are a milder way to go, as unless you're actually allergic to lemon or cucumber, they generally won't hurt you. Moderation is important too - don't drink it all day, every day. People with acid reflux or Barrett's esophagus should avoid lemon juice and any type of citrus though. People just need to do their research before trying these things, and it's good to point that out.