The head of the Drug Enforcement Administration is visiting China this week to discuss combating sales of synthetic drugs, including fentanyl, CNN reports. Acting Administrator Chuck Rosenberg will also discuss new psychoactive substances and money-laundering activities when he meets with Chinese officials.

After China banned 116 synthetic drugs in 2015, the United States saw a significant drop in synthetic drug sales, the article notes. “The change was just immediate in what we saw in America,” DEA spokeswoman Barbara Carreno said. “The stuff just disappeared, and we’re hoping to see some more of that.”

U.S. officials say Chinese manufacturers are selling synthetic fentanyl to Mexican cartels.