Ketamine consumption appears to be rising in Switzerland, according to new wastewater data, reported SRF. Researchers at Swiss Federal Institute of Aquatic Science and Technology (Eawag) analyse sewage samples to estimate drug use, working on the premise that what flows through treatment plants offers a snapshot of consumption patterns.
Figures published by Dromedario, a substance-monitoring portal, for the first half of 2025 show a marked increase in traces of ketamine. The drug is used medically as an anaesthetic but is also popular in club settings, where it is known as “K” or “Ket”.
Frequent use has been linked to dependence, cognitive impairment and severe bladder damage, a condition known as ketamine bladder, which can require surgery, in some cases to remove the bladder.
The highest concentrations were recorded in Zurich, where ketamine levels in wastewater significantly exceed the average of the ten Swiss sites tested. Levels also spike at weekends, suggesting recreational use plays a substantial role. The data cannot distinguish between medical and illicit consumption, but the weekday–weekend gap offers a clue.
A similar pattern is visible for crack cocaine. Researchers do not measure the drug directly, but rather AEME, a chemical produced when crack is smoked. In 2025 levels have risen noticeably, particularly in Zurich and Chur, again with pronounced weekend peaks.
Other substances show the opposite trend. Methamphetamine—commonly known as crystal meth—has declined slightly nationwide since monitoring began in 2021. Cannabis use also appears to have edged down: concentrations of THC-COOH, a breakdown product detectable in urine after consumption, were somewhat lower in the first two quarters of 2025 than in previous years.
Wastewater analysis cannot identify individual users, but it offers a broad barometer of changing habits. For ketamine, at least, the direction of travel is clear.
More on this:
Eawag article (in English)
SRF article (in German)
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