Butterbur’s alleged hay fever-fighting properties have been eyed with scepticism by some scientists over the last few years, but the largest trial conducted to date suggests that an extract from the herb is as effective at alleviating symptoms as a common anti-histamine.

Hayfever, also known as seasonal or intermittent allergic rhinitis, is estimated to affect around 20 percent of people in Western countries - although the true figure may be higher as in many sufferers it is not severe enough to lead them to consult a doctor.