Pellitory (Parietaria officinalis), also known as Pellitory-of-the-wall, has a long history of use in traditional European herbal medicine, primarily as a remedy for urinary and respiratory complaints. Its application to external ulcerations is based on folk medicine practices, where the leaves were sometimes used as poultices or washes to promote healing of wounds and skin ulcers. Historical herbal texts, such as those by Nicholas Culpeper and John Gerard, mention Pellitory for external use on sores and ulcers, attributing to it mild soothing and emollient properties.

However, the evidence supporting Pellitory's effectiveness for external ulcerations is almost entirely anecdotal and rooted in tradition. There are no robust clinical studies or modern scientific investigations that demonstrate a significant wound-healing or antibacterial effect when used topically for ulcerations. The plant contains some flavonoids and mucilage, which may provide a mild soothing effect, but this has not been conclusively shown to translate into clinically meaningful benefits for ulcer healing.

In summary, while there is traditional precedent for Pellitory's topical use on external ulcerations, the evidence is weak and not substantiated by modern research. Its use for this indication should be regarded as a historical practice rather than a scientifically validated treatment.