Hyssop essential oil (Hyssopus officinalis) is characterised by high concentrations of pinocamphone and isopinocamphone (ketones, up to 50% combined), alongside beta-pinene and pinocarvone. The pinocamphone content accounts for its mucolytic and expectorant use in respiratory conditions, though these ketones are also neurotoxic at high doses and contraindicated in epilepsy and pregnancy.^[1] Antiviral activity against HSV-1 has been reported for hyssop extracts.^[2]