The tradition of the holy oil of St Philomena began the first week after the Saint's relics were transferred to Mugnano del Cardinale on 11 August 1805.

For nine days, the population prayed before the saint, and the ninth day was marked by many omens.

During the Mass, a poor widow, Angela Guerriero, prayed with faith for her son Modestino, who was paralysed and could not stand. As soon as she bowed her head she heard a thud beside her, and turning to see if Modestino had fallen, she saw him running down the aisle towards St Philomena to thank her for his recovery. After Mass, Modestine walked through the town and showed everyone his straight legs. Naturally all the bells rang out, and Modestino was accompanied by the drums of the local band . Everyone in the town tried to get into the church for Vespers. Even a woman holding her two-year-old blind child in her arms, a blindness caused by smallpox. She pushed to enter in vain, and during the sermon, when the crowd was on its feet, she slowly managed, inch by inch, to get closer to the altar. He dipped a finger into the oil of the lamp burning before the body of St Philomena, and anointed the child's eyes. Immediately and without pain, the eyelids opened. The eyes saw the light of the lamp and the child laughed with joy.

Every year, donations of oil arrive from devotees and the Centres of the Archconfraternity of Saint Philomena to be blessed on the Feast Day of the Patronage of Saint Philomena, the first Sunday after 10 January (Saint Philomena's birth) . The blessed oil will power the votive lamp in front of the body of St. Philomena and will be distributed to devotees all over the world.