London - Former double Olympic champion Sebastian Coe wants the ban for athletes failing drugs tests to be increased from two to four years, he said on Sunday.
"We have to go back from two years to four years.
"The move down to two did a lot of damage to my sport," Coe, the chairman of last year's London Olympics, told BBC Radio Five Live's Sportsweek programme.
"It is for the clean athletes.
"I don't care about the cheats we weed out.
"These people are trashing my sport."
Coe was speaking after sprinters Tyson Gay of the United States and Asafa Powell of Jamaica, both Olympic and world championship gold medallists, provided positive samples earlier this month. Both have withdrawn from next month's world championships in Moscow.
Coe, who won the Olympic 1 500 metres titles in Moscow in 1980 and Los Angeles in 1984 and is now a vice-president of the International Association of Athletics Federations (IAAF), is concerned people are losing faith in the sport.
"It is depressing. Trust sits at the heart of this," he said.
"I don't think trust is gone entirely but it was a bad day for the sport.
"The big challenge here is to go on fighting, this is not a fight we can afford to lose.
"It is about trust.
"If fans can't trust the athletes and go there knowing what they are watching is questionable, then we will descend to American wrestling where most of the crowd know it is fake and, worryingly, don't care."
Coe believes that athletes are prepared to take risks by cheating as the two-year ban does not take enough time out of their career to be a deterrent.
"If I could bring lifetime bans in I would," he told the BBC.
"The legal inhibitor to be able to do that is profound.
"We are not going to be able to have life bans, they would be challenged and when we have done it we have lost.
"Four years does make people think, it is a big chunk of your career, but two years with appeals is often only 18 months.
"Too many athletes have been prepared to take the risk."