We review the data on the efficacy and tolerability of silexan, a novel preparation from lavender oil for oral use, in the treatment of anxiety disorders and related condition with particular attention to subthreshold generalized anxiety disorder (GAD). Three randomized, double-blind clinical trials were identified which investigated the efficacy of silexan in subsynromal anxiety disorder (vs. placebo; 10 weeks' treatment), in GAD (vs. lorazepam; 6 weeks), and in restlessness and agitation (vs. placebo; 10 weeks) according to DSM-IV and ICD-10 criteria. All trials assessed the participants' anxiety levels using the Hamilton Anxiety Scale (HAMA). Across all trials 280 patients were exposed to silexan 80 mg/day, 37 were treated with lorazepam 0.5 mg/day and 192 received placebo. Average within group HAMA total scores at baseline ranged between 24.7 and 27.1 points. Patients treated with silexan showed average HAMA total score decreases by between 10.4 ± 7.1 and 12.0 ± 7.2 points at week 6 and by between 11.8 ± 7.7 and 16.0 ± 8.3 points at week 10. In GAD silexan and lorazepam showed comparable HAMA total score reductions (90% CI for mean value difference: -2.3; 2.8 points).