File:The remedial grass of St Edrin-Edren - geograph.org.uk - 1250076.jpg

English: The former church of St Edrin or Edern, Llanedren, Pembrokeshire, seen from the southwest. Tradition credited the grass around this former church with the power to cure disease and in particular the bite of a rabid dog. Lewis's Topographical Dictionary of Wales, 1833, states:

"The grass in the churchyard is asserted by many residents in the vicinity to be a specific for preserving both men and cattle from the effects of the bite of a mad dog: by the former it is eaten with bread and butter, and the latter are turned in to graze upon it; and in those which in that condition have eaten it no symptoms of madness have afterwards appeared, while, on the contrary, such as would not have uniformly died in a short time: the grass is the perquisite of the parish clerk, and in the wall of the chancel is a cavity, into which is put whatever persons choose to pay for eating it."

Rabies, or hydrophobia, was endemic in Britain and a constant fear until 1902 when legislation for muzzling dogs finally enabled its eradication. It was always fatal until 1885 when Louis Pasteur introduced his vaccine treatment.