Eucharistic miracle

A Eucharistic miracle is any miracle involving the Eucharist, regarding which the most prominent Christian denominations, especially the Catholic Church, teach that Christ is truly present in the Eucharist, which is by itself a Eucharistic miracle; however, this is to be distinguished from other manifestations of God. Eucharistic miracles are most known and emphasized within the context of the Catholic Church, which distinguishes between divine revelation, such as the Eucharist, and private revelation, such as Eucharistic miracles.

In general, reported Eucharistic miracles usually consist of unexplainable phenomena such as consecrated Hosts visibly transforming into myocardium tissue, being preserved for extremely long stretches of time, surviving being thrown into fire, bleeding, or even sustaining people for decades. In the modern Catholic Church, a special task-force or commission scientifically investigates supposed Eucharistic miracles before deciding whether they are "worthy of belief", in order to differentiate real Eucharistic miracles from cases of contamination by red colored microorganisms, such as Neurospora crassa or Serratia marcescens.

Scientists have advocated for using rigorous methods to detect biological impurities like microbial growth or tissue-like material in samples. As well as to provide standardized, and reproducible scientific analysis rather than relying on anecdotal or uncontrolled investigations. In an analysis of 25 events, none of the Eucharist miracles that could be investigated in such a way showed any proof for the existence of blood, human material other than single epidermal cells or erythrocytes, and may have natural explanations.

As with other private revelations, such as Marian apparitions, belief in approved miracles is not mandated by the Catholic Church, but often serves to reassure believers of God's presence or as the means to "send a message" to the population at large.