Catholic Scientists Debunk Assertions of Scientific Proof for Eucharistic Miracles
Peer-reviewed studies respond to website on miracles created by Italian teenager soon to be canonised by Pope Francis
Catholics have shown a renewed interest in the miracles after Pope Francis announced on July 1 that he would canonize Carlo Acutis, a tech-savvy Italian teenager who assembled an exhibition cataloguing 160 eucharistic miracles from around the world. Acutis died of leukemia in 2016.
The exhibition curated by Blessed Acutis is currently showing at the Shrine of St. Augustine, in Ramsgate, England, after being exhibited in thousands of parishes and at more than 100 universities. Organizers say that the exhibition has already been booked for half of 2025.
The miracles, which have been reported since A.D. 750, feature consecrated communion wafers displaying the appearance of blood (and sometimes human tissue) — often after the wafer accidentally fell to the ground or in response to a priest’s unbelief in the doctrine of transubstantiation.
However, Catholic scientists are now urging the faithful to be cautious about claims that eucharistic miracles have been scientifically proven, as unconsecrated hosts tested under similar conditions have also shown similar “bleeding” appearances.
Peer-reviewed studies published by Catholic scientists who believe in Christ’s real presence in the Eucharist have also dismissed assertions that the miracles were validated by research carried out by the World Health Organization (WHO) and the United Nations (UN).
Lanciano Miracle
One such miracle is said to have occurred in Lanciano, Italy, where a monk who doubted Christ’s real presence in the sacred elements found that the host was miraculously changed into flesh and the wine into blood as he recited the prayer of consecration.
The coagulated blood and flesh were preserved in the cathedral and examined in 1971 by anatomical pathologist Dr. Odoardo Linoli, who published his findings in the Italian medical journal Quaderni Sclavo di Diagnostica — noting that the flesh consists of heart muscle tissue and the blood type is AB. Mold and the residue of small insects and maggots also were present.
According to Linoli, “The blood group is the same as that of the man of the holy Shroud of Turin, and it is particular because it has the characteristics of a man who was born and lived in the Middle East regions.”
“Prof. Linoli’s investigations are scientifically impeccable,” Dr. Franco Serafini writes in his nonacademic book A Cardiologist Examines Jesus: The Stunning Science Behind Eucharistic Miracles. However, he admits that “there are currently no reliable historical documents about the origin of these relics.”
But in a peer-reviewed article published November 13 in the Journal of Forensic Science and Research, Catholic scientist Dr. Kelly Kearse and his colleague Dr. Frank Ligaj challenge the Linoli and Serafini’s conclusions, highlighting flawed test methods.
Eucharistic miracles should also be defended from the friendly fire of various scientists and popularizers who dish up studies and publish inaccurate articles.
“[I]t cannot be declared that the results are specific for human blood as very limited demonstration is given regarding the potential cross-reactivity of the antisera used with only two other species tested, bovine and rabbit,” they observe.
Concerning the AB blood type found in Lanciano, the scientists note in an article titled “Scientific Analysis of Eucharistic Miracles: Importance of a Standardization in Evaluation” that “doubts have been raised regarding the validity of such results as bacteria also express AB antigens.”
“More contemporary techniques that distinguish between bacterial and human AB antigens may help clarify the accuracy of the findings of shared AB expression among various Eucharistic miracles and Christian relics,” like the Shroud of Turin, they write.
While miraculous wafers shared the AB blood type with bloody fibers from the Shroud, the scientists note that “bacteria also express AB antigens, providing a practical explanation for similar results.” Also, both fibers “of the Shroud and various Eucharistic miracles have been reported to be substantially contaminated with both bacteria and fungi.”
Debunking the WHO Investigation
Meanwhile, assertions that WHO research has validated the Lanciano miracle and similar occurrences continue to circulate, despite Catholic scientists debunking such claims.
According to a recent article in the National Catholic Register, “Scientific studies in 1970, later supported by the World Health Organization’s own research,” showed findings of heart muscle tissue and AB blood type.
The Catholic media agency Zenit states that the WHO Higher Council appointed a scientific commission to verify Linoli’s conclusions in 1973 and carried out its research “over 15 months with a total of 500 examinations.”
However, in his book Serafini says he “personally unmasked” the “elusive” WHO report and dismisses it as a “cheap ideological fake” and a “slapdash document” which uses data “mostly obtained from Egyptian mummies and not from the tissue specimens of Lanciano.”
Kearse and Ligaj also report that they and others “searched in vain for any results or documentation from this report and contacted both the WHO and UN, who had no records of any investigation during that period.”
“I, myself, contacted the WHO several years ago, and they had no record of any such report being conducted,” Kearse tells The Stream.
“The damage is enormous,” Serafini laments. “Eucharistic miracles should also be defended from the friendly fire of various scientists and popularizers who dish up studies and publish inaccurate articles. Even if they do this in good faith, their ‘works’ are biased, unable to withstand serious and rational criticism, and ultimately end up being absolutely counterproductive.”
Buenos Aires Miracle
A second miracle reported in the Church of Santa Maria y Caballito Almagro on August 18, 1996, has gained popularity because it occurred while Pope Francis (known at the time as Archbishop Jorge Bergoglio) was heading the archdiocese of Buenos Aires — the site of the miracle.
Following ecclesiastical protocol, the parish priest, Fr. Alejandro Pezet, placed a consecrated host which was found discarded at the back of the church into a glass of water for it to dissolve. On August 26, he saw that the host had been transformed into a piece of bloody tissue and informed Bergoglio of it.
An investigation was conducted in 1999 under Ricardo Castanon Gomez, a clinical psychologist who specialized in brain chemistry. Histological samples were sent to a team of experts, including Dr. Fred Zugibe, a pathologist specializing in cardiology.
Zugibe concluded that the sample was from “tissues of the heart, undergoing degenerative changes of the myocardium, and these changes are due to the fact that the cells are inflamed, and it is the left ventricle.” Experts also reported finding human DNA in the samples.
More than ever, this is a time to assert that the claims of scientific findings are rarely absolute.
However, Kearse and Ligaj note that the “primary experts … sought out were pathologists or cardiologists, indicating that the assumption had likely been made that this was human (cardiac) tissue.”
“If the transformation into cardiac tissue is valid and originated from a single source, then the HLA profiles [human leukocyte antigens which are markers on most cells in the human body] should be identical, without exception, worldwide,” Kearse tells The Stream.
The research should have been conducted in “true blind fashion” by “mix[ing] in with the experimental slides various control slides prepared in the same manner,” he writes. And “the very low concentration of human DNA that was recovered is characteristic of contaminating DNA, the likely result of someone touching the sample.”
The paper identifies Zugibe’s failure to “consider other possible non-miraculous sources of DNA that could exist in the sample, such as bacteria, fungi, and plants (wheat)” especially since “wheat DNA has been shown to survive the baking process under relatively high temperatures and exposure conditions and to be successfully amplified by PCR.”
The scientists quote Dr. Tracy Trasancos, a Catholic scientist who agreed that the DNA report Zugibe presented was “an overexaggeration of the findings.”
“Bleeding Host” in Tyrol
In a corresponding study, four scientists investigated the case of a “bleeding host” found at the Franciscan Church of Schwarz, Tyrol, in 2016.
Their peer-reviewed paper, published in the Annals of Clinical and Medical Case Reports in August 2023, discovered “bacterial and fungal contamination of the host (wafer), but no solid proof of mammalian tissue.” Moreover, subsequent DNA analyses failed due to limited material made available by the friars.
“Bacteria that can colonize flour/bread/wafer and give it red colour, sometimes even resembling blood streams, have been discussed to underly the so-called bleeding event,” the authors note. “The condition in the vasculum the friars had placed the host under discussion fairly presents an ideal condition for growth of such bacteria colonies.”
Turning Unconsecrated Wafers into “Bleeding Hosts”
While Kearse and Ligaj also expose flawed methods of validating eucharistic miracles in Sokolka, Poland (2008); Legnica, Poland (2013); and Tyrol, Austria (2016); they show “for the first time that ordinary, non-consecrated wafers show similar appearances when treated in a like manner.”
After placing unconsecrated wheat communion wafers on or near the floor for several days and transferring them to containers of tap water to reproduce what has been described in various miracle reports, the scientists found in approximately 15% of the cases that a bright red area was growing on the remaining wafer portion some seven to 10 days later.
While other researchers have posited the bacteria Serratia marcescens is one possible cause of the red, blood-like appearance, “the prevalence of DNA from other species (plant, bacterial, fungal) in non-consecrated wafers offers a plausible alternative to the findings of previous Eucharistic miracle investigations,” write Kearse and Ligaj.
DNA may originate from the wheat wafer itself, or from bacteria and fungi. Moreover, DNA from miracle wafers could be problematic due to contamination by multiple individuals, they add. Since multiple types of non-human DNA exist in unconsecrated wafers, this provides an alternative explanation for such findings.
Catholics Scientists Affirm the Real Presence
Kearse and Ligaj maintain that “the purpose of their article is not to suggest that all Eucharistic miracles should be viewed as fallacious; rather, the aim is to emphasise that solid scientific practice should be used in the evaluation of such occurrences so that a true assessment may take place.
“One of the major issues with the subject of Eucharistic miracles is that no standard scientific protocol exists for their examination,” they explain, recommending a “minimum procedure” as a “starting point to standardise the scientific evaluation of such occurrences.”
A careful appraisal both for and against the scientific claims is necessary.
In particular, they recommend taking DNA swab samples from people handling the consecrated hosts, and using a meticulously documented chain of custody involving both written and photographic formats at each stage of the examination.
A “scientific expectation from any such investigation is that the results would be subject to a broader peer-review in the form of journal publication, which is standard scientific practice,” Kearse tells The Stream.
“Let me add that I consider myself a faithful Catholic. I am an adult convert and have been a Eucharistic minister for over twenty years,” he added.
Catholics Not Obliged to Believe in Eucharistic Miracles
Catholics are “not obliged to believe” in the miracles, but they can be “useful and fruitful aids to faith,” Bishop Raffaello Martinelli, a former official at the Congregation for the Doctrine of the Faith, writes in guidance notes for the Acutis exhibition.
The exhibition website does not claim that the miracles have been scientifically validated. It also does not cite any peer-reviewed studies or scientific research as confirmation of the miracles.
Similarly, Trasancos’s book Behold, It is I: Scripture, Tradition, and Science on the Real Presence cautions that “a careful appraisal both for and against the scientific claims is necessary.”
“The data from these reports, which for various reasons is inconclusive, begs the ultimate question of the certainty of faith,” she writes. “More than ever, this is a time to assert that the claims of scientific findings are rarely absolute.”
Originally published in The Stream.
Dr. Jules Gomes, (BA, BD, MTh, PhD), has a doctorate in biblical studies from the University of Cambridge. Currently a Vatican-accredited journalist based in Rome, he is the author of five books and several academic articles. Gomes lectured at Catholic and Protestant seminaries and universities and was canon theologian and artistic director at Liverpool Cathedral.
Another extremely well-researched article. Authentic cases of miracles and diabolical possession are extremely rare. However, people want to believe in them to support their belief in the existence of a spiritual world and life after death. A lot of money has been made by towns where so-called apparitions were said to have occurred. Gomes should not be falsely accused of denying miracles. He wants to protect people, especially Catholics, from losing their faith if it were proven that the tears of the statue of the Blessed Virgin Mary were caused by a broken water pipe in the ceiling of the church.