New psychoactive substances (NPS) are health-hazardous through unpredictable toxicity and effects and largely unknown epidemiology, motivating studies of the latter. Up to 138 NPS were retrospectively identified using liquid chromatography-high resolution mass spectrometry data from all 34 183 oral fluid drug samples collected in one Swedish health care region 2019-2020 representing 9468 psychiatric and addiction care patients. In total, 618 findings representing 58 NPS were detected in 481 samples from 201 patients.
