The Athletics Integrity Unit (AIU) has provisionally suspended Kenyan marathon world record holder Ruth Chepng’etich after she tested positive for a banned substance.

The suspension follows the detection of hydrochlorothiazide (HCTZ), a diuretic prohibited by the World Anti-Doping Agency (WADA), in a sample collected from Chepng’etich on March 14, 2025.

“The AIU has provisionally suspended Ruth Chepng’etich (Kenya) for the presence and use of a prohibited substance (hydrochlorothiazide),” read a post by AIU on their X on July 17, 2025.

The development casts a shadow over the career of the celebrated Kenyan athlete, whose marathon world record of 2:09:56 at the 2024 Chicago Marathon stunned the athletics world. Chepng’etich is also a three-time Chicago Marathon winner and the 2019 World Marathon Champion.

The AIU announced the suspension after a detailed investigation triggered by her positive test, reported to the unit on April 3, 2025. According to the AIU, the urine sample contained an estimated concentration of 3800 ng/mL of hydrochlorothiazide—far exceeding WADA’s minimum reporting level of 20 ng/mL.

HCTZ is widely used in clinical settings to treat hypertension and fluid retention, but in sports, it falls under WADA’s S5 category: Diuretics and Masking Agents. These substances are prohibited at all times due to their potential to hide the presence of other banned drugs in an athlete’s system.

In a detailed statement, AIU Head Brett Clothier explained the chronology of the case and the rationale behind the decision. He confirmed that Chepng’etich was notified of the positive test and interviewed by AIU officials in Kenya on April 16. She cooperated fully with the investigation.

Clothier noted that under the World Anti-Doping Code, a provisional suspension is not mandatory when diuretics and masking agents are involved. At the time of notification, the AIU did not impose one immediately. However, on April 19, Chepng’etich voluntarily accepted a provisional suspension while the AIU continued its enquiries.

“On 17 July 2025, following further investigations, the AIU issued a Notice of Charge and imposed its own provisional suspension,” Clothier stated. He also emphasised that Chepng’etich has the right to have her case heard before a disciplinary tribunal and that no further comments will be made until the case is concluded.

As a specified substance under WADA rules, HCTZ carries a standard sanction of two years of ineligibility. However, the ban could be adjusted depending on the outcome of the disciplinary process. The AIU acknowledged Chepng’etich’s cooperation but highlighted that the unusually high concentration of HCTZ in her sample necessitated decisive action.

The Athletics Integrity Unit operates as an independent body under World Athletics, handling all integrity issues in athletics, from doping cases to competition manipulation and fraudulent conduct. Its mandate is to protect clean athletes and ensure fair competition globally.

Chepng’etich now faces an uncertain future, as the athletics world waits for the outcome of the tribunal. Her case raises renewed concerns about integrity in elite sports and the impact of doping scandals on the credibility of Kenyan athletics.

Further details will remain confidential until the disciplinary process is complete.