The book follows Kiedis' life from his birth in 1962 to early 2004. It follows Kiedis into the depth of his experiences with drug addiction. The title name was taken from the single "Scar Tissue" released five years earlier on the Red Hot Chili Peppers album Californication.

According to the book, Kiedis' first drug experience was with his father Blackie Dammett, a former drug dealer, at age eleven. By the time his band formed and became more popular in the 1980s, he and former bandmate Hillel Slovak had severe drug addictions. On Slovak's death from overdose in 1988, Kiedis writes that he was so shaken that he skipped town, missing the funeral. Kiedis had no idea what to do without his friend. His death only made matters worse, and caused him to do more and more hardcore drugs.[1] He attempted to get clean afterwards but relapsed in 1994 after being given medications while getting a tooth pulled. Later on, he reveals that he was not actually clean, as he claimed at the time, during the late-nineties Californication era of the band's existence. He claims his new clean date is December 24, 2000. The book reports very specific dates, such as when Kiedis was conceived.

In a June 2016 interview, Kiedis stated he had regrets of writing Scar Tissue saying “I did regret the book for a while as there was some pain caused then, I started seeing the long term positive reverberating. People were reading it in hospitals, in prisons and schools and it was having a positive effect. I realised that the whole point of writing that book wasn’t for me, but to show that somebody can go all the way down and come all the way back and have a productive, successful happy interesting life. And so whatever shame, pain or difficulty or discomfort I went through, then it was worth it because I get so many people coming up to me saying their kids had read it and got their act together because of it.” [2]