The rules on the use of cannabis by athletes should be reviewed, World Athletics President Sebastian Coe said on Tuesday, after rising track and field star Sha'Carri Richardson will miss the Tokyo Games following a positive test for the substance.

The sprinter, aiming to become the first American in 25 years to win the women's 100m Olympic title after Marion Jones was stripped of the 2000 gold, tested positive for cannabis last month at the US Olympic Track & Field trials after streaking to victory in the 100m.

She was hit with a one-month ban and had her trials results annulled, ruling her out of the Tokyo Games. Richardson said at the time her action came while she was dealing with the news of the death of her mother. She also took the drug in Oregon, where its use is legal.

"It should be," Coe told a small group of reporters on Tuesday when asked if the rule should be reviewd. "It is sensible, as nothing is set in tablets of stone."

"You adapt and occasionally reassess. The Athletics Integrity Unit is absolutely the best organisation to look at this," said Coe, a former double Olympic 1500m champion.

"I have spoken to (AIU chairman) David Howman about that. The AIU will look at this in the light of current circumstances."

Richardson's suspension sparked an outpouring of sympathy, including from President Joe Biden, and calls for a review of anti-doping rules. The Games, however, will take place without one of the biggest young names in athletics.

Cannabis is banned by the World Anti-Doping Agency (WADA) but if athletes can prove that ingestion is unrelated to performance, then receive a shorter ban than the usual two or four years for other banned substances.

"I am sorry for her," Coe said. "That we have lost an outstanding talent."

"It is not unreasonable to have a review on it. She will bounce back. It is a loss to the competition."