Professor Green gave up smoking because it was affecting his voice to the point where he was "spitting blood".
The 'Monster' hitmaker said he was forced to give up his old vices of smoking and drinking on stage when he realised the effect it was having on his throat.
He said: "I don't smoke anymore, I had to knock it on the head. After all the years I'd been smoking, it was high time that I did. I'd be smoking onstage, I'd have my whisky onstage I'd come off and my throat would be ripped to shreds. To the extent where I was spitting blood."
The singer's backstage drink of choice is now herbal tea before he goes on to do his vocal warm-ups.
He added: "It's alright, gotta have a throat coat tea because my voice is going, innit."
It is not only smoking that has threatened Green's throat - he nearly lost his voice, and even his life, after being stabbed in the neck by thug Anthony Jones, who has been convicted of wounding with intent and faces a "very substantial" jail term for the 2009 attack.
About his giving evidence in the trial, Green added: "It's good to have that out of the way. Hopefully that's the end of that chapter I'm sure you can see a difference in me. Six hours sleep and some sexy time, it works wonders."