Kenya's 2021 Boston Marathon winner Diana Kipyokei and compatriot Betty Wilson Lempus have been provisionally suspended following failed drug tests.
Both Kipyokei, 28, and Lempus, 31, have also been charged with obstructing the Athletics Integrity Unit's (AIU) investigation by providing false information or documentation.
The two athletes tested positive for triamcinolone acetonide.
It means 10 Kenyan athletes have tested positive for the substance since 2021.
In comparison, only two other athletes have returned positive tests for the banned substance during the same period and the AIU noted the cases "are part of a recent trend in Kenyan athletics".
The AIU said that "after extensive investigations", Kipyokei and Lempus had been charged "with various breaches of the World Athletics Anti-Doping Rules".
It added: "These alleged anti-doping rule violations stem from probes into the information provided by the athletes to explain Adverse Analytical Findings (AAF) for metabolites of triamcinolone acetonide in samples."
Kipyokei, who would be stripped of her Boston title if the charges are proven, had a sample taken after her victory last October, while Lempus was tested following her win at the Paris Half Marathon in September last year.
Triamcinolone acetonide is classified as a glucocorticoid, which are commonly used as therapeutic substances. Their use is permitted if athletes can produce an exemption or proof that administration is not through a prohibited route.
They are prohibited in competition, when administered in certain ways, because "there is clear evidence of systemic effects which could potentially enhance performance and be harmful to health", the AIU said.
The AIU banned Kenyan marathon runner Mark Kangogo for three years on Thursday for the use of triamcinolone acetonide and norandrosterone.