Ronnie Wood was always aware of how many drugs his body could cope with.
The Rolling Stones rocker - who has been to rehab seven times to be treated for alcoholism - saw others fall ill after heavy use of illegal substances but insists he knows his limits.
He said: ''I had kind of a cut-off switch. People would be teasing you, 'Come on, have some more,' and I'd pretend to take the pill and then throw it away.
''They would carry on and bloody end up in hospital but I always had the sense in the back of my mind, no matter how out of it I was, of the body's ceiling.''
However, he had to deal with his relapse a few years ago which led to the breakdown of his marriage to Jo Wood.
He told the Independent newspaper: ''I'd gone a long while without drinking and drugging, and I thought, 'I can do it!' So I dabbled again and it would lad to these mad, deranged arguments and in the end it all exploded in the street.''
One of Ronnie's friends who struggled to know how much to take was the late Who drummer Keith Moon, and the guitarist confesses he was always shocked at the quantities of drugs his pal could consume.
He added: ''I remember Keith and the Valium. He'd give you like a handful and I'd have like a half and he'd have the whole lot!''