‘At least you know you’re safe with herbs,’ patients sometimes say. But it’s not always true.
Some plants are extremely toxic, and many others – including everyday vegetables like cabbage and lettuce – contain compounds that would be harmful if you ate huge amounts of them. In between, there is an enormous grey area.
The European Herbal Practitioners Association (EHPA) has recently advised that plants containing pyrrolizidine alkaloids should not be taken internally. Comfrey and borage are the best known examples, but the list also includes coltsfoot, alkanet and other less popular herbs. We’ve known for a long time that these alkaloids can damage the liver, and responsible herbalists have only used them in creams and lotions for over a decade. Now, new research has reinforced this position.
It’s really a ‘better safe than sorry’ situation. We’re not sure yet how much is safe, and it’s a risk not worth taking
So for now, avoid comfrey and borage teas, or using comfrey as a vegetable (it used to be recommended for vegans, as it contains high levels of vitamin B12). But don’t worry about comfrey cream or other external preparations. They are perfectly safe, and so is starflower oil, which is extracted from borage seed and does not contain pyrrolizidine alkaloids.
And the guidelines may change again; watch this space.