St. John's Wort (Hypericum perforatum) is a popular herbal antidepressant in Germany and the usa. In the Netherlands the attention for its use is growing. St. John's wort in a dosage of 900 mg/day is more effective than placebo and probably as effective as tricyclic antidepressants and ssri's, for the treatment of mild to moderate depression. St. John's wort is associated with substantially fewer side effects. However, several reports have raised the possibility of interactions between St. John's wort and various perscribed drugs. Recently precipitation of (hypo)mania, acute intoxication and serotonergic syndrome induced bij St. John's wort were reported. We present a case of delirium temporally associated with the use of St. John's wort.