The Kenyan runner tested positive for the banned substance hydroklortiazid in March this year and was then temporarily suspended pending further investigation.
Hydroklortiazid can make it more difficult to detect other doping-classified substances during doping tests, as well as contribute to rapid weight loss. It is usually used for elevated blood pressure.
The 31-year-old has admitted to the doping offense and is now suspended for three years.
The suspension applies from April 19 this year and for three years onwards.
Last year, Chepngetich set a new world record in the marathon with a time of 2.09.56 during the Chicago Marathon. She also won the marathon race at the World Championship 2019 in Qatar.
