The use of thujone, a monoterpene ketone often present in sage (Salvia officinalis L.) or wormwood (Artemisia absinthium L.), for the treatment of diabetes mellitus was recently suggested in a study published in this journal. Evidence was based on the findings obtained in a diabetic rat model. After oral treatment with thujone (5 mg/kg bodyweight (bw)/day for 28 days), the cholesterol and triglyceride levels were significantly adjusted to normal levels when compared to diabetic, untreated rats. While these results sound promising and worthy of further investigation, the well-defined profile of the adverse properties of thujone demands a cautious interpretation of these results. The therapeutic margin of thujone appears to be small, as a dose-related incidence of seizures was noted in 2-year National Toxicology Program studies in rats and mice. The dose level in the diabetic rat study is also considerably higher than a daily intake that is acceptable for humans (0.1 mg/kg bw/day).