The chapel is thought to have been built towards the end of the fifteenth century, in late Gothic style, as a small refuge for wayfarers, the ill and the destitute. During the Reformation in the 1530s it was seized by the Danish Crown and left empty. The abandoned building was further damaged when Vä was plundered by Swedish forces in 1569 and again in 1612, on the latter occasion probably being destroyed by fire.
What survives today are the partially ruined walls of the nave and chancel. The nave measures roughly 16 by 8.5 metres and the chancel about 6 by 5 metres. Most of the standing walls, one to four metres high, are built of rough fieldstone, but the western gable stands apart: it rises to some ten metres, topped above the stonework by a brick gable end, and remains the ruin's most striking feature.
Local tradition claims the chapel was founded by Queen Gertrud of Denmark, wife of King Knud VI, who is said to have lived in Vä and to have been buried there, naming the chapel after her namesake Saint Gertrude of Nivelles, patroness of the poor, the sick and travellers. This story appears in a seventeenth-century account, but historians consider it almost certainly untrue, since the chapel's architectural style points to a fifteenth-century date and the cult of Saint Gertrude is not recorded in Denmark before the fourteenth century.
The ruin was excavated and the west gable restored in the 1930s, after having lain hidden for a long period beneath a layer of soil around 1.5 metres deep. The excavation confirmed that the chapel had been destroyed by fire, and fragments of a fire-damaged bronze bell were found near the east gable. Two later graves were uncovered in the chancel, along with two column bases and sections of column shafts, which are now displayed within the ruin. A gravestone found nearby in 1939, reused as a paving stone over a local stream, dates from the early seventeenth century and is also kept at the site.