Thai women's badminton player Pitchamon Opatniputh became the first known doping case at the Asian Games in Japan on Monday, testers said.
The 19-year-old returned a positive sample for the banned substance furosemide and has been provisionally suspended, the International testing Agency said.
The teenager, who is ranked 18th in the world and regarded as a rising star back home, had been due to face China on Tuesday in the team event.
The first full day of badminton action at Asia's biggest sporting spectacular was on Sunday.
"The athlete is prevented from competing, training, coaching, or participating in any activity during the Asian Games Aichi-Nagoya 2026," the ITA said.
The agency noted that Pitchamon can challenge the provisional suspension at the Court of Arbitration for Sport (CAS).
"The athlete also has the right to request the analysis of the B-sample," it added.
Furosemide can be used by competitors to excrete water for rapid weight loss.
The sample was collected by the ITA during out-of-competition testing on September 17.