I did a good number on my liver by drinking lots of alcohol and doing drugs for several years. About a year and a half I spent every single day drunk, some nights I downed full handles of vodka.
Mainly to stuff down my fears and emotional garbage.
I've been mostly clean for a long time, save the ocassional party. After my last one, believe you me I'm DONE with alcohol. Not worth it.
But I'm sure my liver can't be too happy with me, so I'll give a cleanse a go.