Many thanks for your response, which does help somewhat to reassure.
The ironic thing is that we have a herb garden with Wormwood in it (we bought it simply to look good amongst the wide range of herbs we eat) but have never tasted the plant itself. Horses are kept in the adjoining paddock and we had no idea that it was particularly dangerous/fatal to them.
I suppose my main concern as a parent is towards my children - taking Wormwood when it arrives in the post myslef is a decision I can take fairly easily, but giving it to children may seen a bit more problematic.
Do you know what sort of dosage is OK for children (aged around 10 to 13)?