The oldest and most famous Eucharistic miracle on record. A Basilian monk, wrestling with doubt about the Real Presence, was celebrating Mass in a small church when, at the words of consecration, the host visibly turned to flesh and the wine to blood, which then coagulated into five uneven clots.

The relics have remained on display ever since, and in 1970–71 the Church permitted a formal scientific study. Researchers identified the flesh as human cardiac tissue and the blood as human blood type AB — findings the investigating team said they could not explain by natural means. The relics are venerated today in the Church of St. Francis in Lanciano.

A German priest, Peter of Prague, stopped in Bolsena while on pilgrimage to Rome. Like the monk at Lanciano centuries before him, he privately doubted that Christ was truly present in the consecrated host. While celebrating Mass over the tomb of St. Christina, the host began to bleed at the consecration, staining his hands and the altar linen.

Shaken, the priest brought the bloodstained linen to nearby Orvieto, where Pope Urban IV was in residence. After an investigation, the Pope had the relic enshrined — and, moved by the event, commissioned St. Thomas Aquinas to compose the prayers for a new feast: Corpus Christi. Those texts gave the Church two hymns still sung at Adoration today, Tantum Ergo and O Salutaris Hostia.

Unlike the others, this miracle isn’t a single moment but nearly three centuries of unbroken preservation. In August 1730, thieves broke into the Church of St. Francis and stole a ciborium holding 351 consecrated hosts. Three days later, parishioners found the hosts — dusty but intact — inside an alms box at a nearby church.

Rather than decaying as ordinary bread would, the hosts remained fresh. Formal investigations in 1780 and 1789 confirmed they showed no sign of corruption, and modern testing in 2014 reached the same conclusion. Roughly 230 of the original hosts are still venerated today in the Basilica of San Francesco.

At a parish in Buenos Aires, a dropped consecrated host was found discarded at the back of the church. Following Church practice for a host that can’t be reverently consumed, the priest placed it in water inside the tabernacle, expecting it to dissolve. Days later, it hadn’t dissolved — instead, it had visibly changed into a substance resembling bloodied tissue.

A sample was later sent, without explanation of its origin, to a cardiac pathologist in New York. His analysis identified living heart tissue under inflammation — and he reported the white blood cells were still active, something he said should have been impossible if the sample had come from tissue sitting in water for years. The investigation was overseen by the then-Auxiliary Bishop of Buenos Aires, Jorge Bergoglio — later Pope Francis.

During Sunday Mass at St. Anthony’s Church, a consecrated host slipped from the priest’s hands during Communion. Following normal procedure, it was placed in water to dissolve. When a sister opened the container days later, most of the host had dissolved as expected — but a small, bright red, tissue-like clot remained at its center.

The Archbishop of Białystok ordered an independent histopathological study. Two pathology professors at the Medical University of Białystok examined the sample under modern microscopy and identified it as heart muscle tissue, consistent with tissue from a person under extreme physical stress. The Church declared the event worthy of belief, and the relic remains on display in Sokółka today.

Considered second only to Lanciano in importance among Eucharistic miracles. A woman, desperate over her husband’s infidelity, consulted a sorceress who told her a consecrated host could be used to win back his affection. She received Communion, hid the host in her veil, and carried it home — where it began to bleed heavily.

Frightened, she hid it in a chest. That night, a bright light poured from the chest, waking the household. The couple confessed to their parish priest, and the bleeding host was enshrined in wax, later encased in a glass reliquary that has been venerated for over 750 years in what is now called the Church of the Holy Miracle. Several popes have granted pilgrims plenary indulgences for visiting it.

During a parish retreat of about 600 people at St. Martin of Tours in Tixtla, a religious sister helping distribute Communion turned to the celebrant in tears — a host in her ciborium had begun seeping a reddish substance. The diocese opened a formal investigation three years later, led by a researcher who had also studied the Buenos Aires miracle a decade earlier.

Testing between 2009 and 2012 identified the substance as human blood, type AB — the same rare finding reported at Lanciano and Buenos Aires — with intact white blood cells and active immune cells still present years after the event. In 2013, the Bishop of Chilpancingo-Chilapa formally recognized it as a “Divine Sign.”

On Christmas Day 2013, a priest at St. Hyacinth’s Shrine accidentally dropped a consecrated host during Communion. Following standard practice, it was placed in water to dissolve. Two weeks later, it had only partly dissolved, and a red stain had formed across part of its surface.

The diocese commissioned two independent forensic institutes, in Wrocław and Szczecin, to examine a sample. Both identified the tissue as resembling human heart muscle showing changes typical of extreme physical stress, and mitochondrial testing confirmed the DNA was human. In 2016, after review by the Vatican’s Congregation for the Doctrine of the Faith, the Bishop of Legnica approved the relic for public veneration.