California prosecutors are cracking down on kava-drinking motorists who are driving under the intoxicating influence of the herbal tea.

Following their first successful conviction in June, San Mateo County prosecutors have filed three other cases, after about a dozen motorists had been pulled over in recent years, said San Mateo Deputy District Attorney Chris Feasel on Monday.

Kava, while not considered a drug by federal health officials, is classified by the U.S. Food and Drug Administration as a nutritional supplement that can be used to relieve anxiety.

Motorists under the influence of Kava had a “thousand-yard stare,” Feasel said. “They’re drooling on themselves sometimes, their motor function is so bad,” he added.

He said that police had pulled over kava-addled motorists who were swerving, veering into other lanes and drifting on to the road’s shoulder.

“Kava basically has the opposite effect of alcohol,” Feasel said. “Kava affects your motor skills before it affects your mental abilities.”

The June conviction is believed to be only the second successful one in the country, following a 1996 case in Utah.

In the pending cases, motorists have admitted to drinking between 10 to 20 bowls of the bitter tea, which comes from the kava root, a member of the black pepper family.

“We’re cracking down on DUI drivers,” Feasel said. “Whether it’s driving under the influence of kava, or a good merlot or Advil, you’re going to be prosecuted.”