Kava Kava

Kava is the clearest case in this field of an effective botanical undone by manufacturing. A Cochrane review of randomised trials found kava extract significantly more effective than placebo for anxiety, with an effect size that compares favourably to many pharmaceutical options, and unlike benzodiazepines it does not appear to impair cognition or produce dependence. Then, between 1998 and 2002, more than seventy cases of severe hepatotoxicity including fatalities and transplants were reported in Europe, and Germany, Switzerland, France and others banned it. Subsequent analysis identified probable causes that were not intrinsic to the plant: European manufacturers used acetone and ethanol extraction, which pulls out hepatotoxic constituents such as pipermethystine and flavokavain B that traditional water preparation leaves behind; some products used aerial parts, stem peelings and leaves rather than the root; and non-noble cultivars, traditionally avoided, entered the supply. Traditional Pacific water-based root preparations, consumed for centuries in far larger quantities, have no comparable signal. The pragmatic conclusion is that kava can be used, but only as an aqueous extract of noble cultivar root, with baseline and periodic liver enzyme monitoring, avoiding alcohol and paracetamol, and stopping at any sign of jaundice or dark urine.