Kneeling at the communion rail on Sunday, Margaret Ashley noticed that the man who drank from the chalice before her had a wretched cold. Nevertheless, she drank from the same cup -- and two days later, had chills and fever and a throat that felt like an open wound.

Is holy communion from a common cup hazardous to your health?

"There's not a priest in the world who hasn't had that thought," said the Rev. Jack Woodard of the Episcopal Church of St. Stephen and the Incarnation in the District of Columbia.

The American Medical Association hedges on the issue: "As far as we know, there have been no cases of transmission of germs to communicants using a common cup. The alcoholic content of the wine, plus the hygienic practice of wiping the cup and turning it to a new position for each communicant seems to remove any danger of disease."

But the national Center for Disease Control in Atlanta says there are some dangers.

"We believe that there are risks, albeit small, of disease transmission from a common vessel used for religious communion," says George F. Mallison, assistant director of the Center's Bacterial Diseases Division.

"In addition to syphilitic lesions of the mouth . . . mononucleosis . . . also presumably could be transmitted by a common cup. In addition, mumps, some acute respiratory infections and herpes virus infections [cold sores] can be spread by virus in saliva of carriers, and Vincent's angina [which causes trenchmouth] also might be spread," he said.

Common cup communion has long been poracticed by Anglicans and some Lutherans, and for a year and a half by Roman Catholics as well. Previously, only priests drank from the chalice at most Catholic masses. But recent liturgical change permits the entire congregation to drink from the chalice as well as receive the communion wafer at all eucharists.

The change has been welcomed by many faithful, who find in it an enhancement of their spiritual life. But some, particularly those with medical training, are concerned.

"As a Catholic and a dentist, I think [common-cup communion] is not a great idea," said Dr. John Droter, who practices in Camp Springs.

"If you owned a restaurant, there's no way the public health people would let you get away with just wiping the cups and putting them back on the table," he said. "If there is no danger [of contamination from the common cup] then why do I have to sterilize all my [dental] instruments?" he reasoned.

As for the AMA statement, Droter pointed out that the organization is "under attack on a lot of fronts; they don't want to get involved in a religious issue."

He said that at communion time during masses at his parish -- St Columba's of Oxon Hill -- many doctors and dentists choose not to drink from the chalice.

Episcopalians, like Catholics, believe that the wine, when consecrated by a priest, is "transubstantiated" into the blood of Christ.

Say Episcopalian Rev. Woodward, "I have decided that faith in God and faith in the alcohhol in the wine will take care of me. I think, theologically, that if we believe that it [the wine] is the blood of Christ and new life for us, then we don't need to worry about its spreading disease."

Some worhshippers resolve their reluctance to drink from the common cup by "intinction," dipping the communion bread in the wine.

But unless a separate chalice is used, they are still exposed to any bacteria that may have contaminated the cup and its contents.

Other denominations that celebrate communion distribute the wine -- or grape juice, in some congregations -- in tiny individual on trays. Eastern Orthdox priest spoon communion from the chalice directly into the mouths of communicants.

Dr. Lawrence Ziemianski, like Dr. Droter a dentist and Catholic parishioner at St. Columba's, says he is caught between his professional judgment and his religious duties as a deacon who assist the priest during communion.

"Frankly, from the standpoint of scinece, medicine and bacteriology, it presents a potential problem," he said."We were always taught that there are more bacteria in the mouth than a sewers of London." But, he added, "I am conscious of the spiritual significance" of sharing in communion.

Another doctor and devout Christian, Dr. Charles S. Tidball, serves on both the medical faculty of George Washington University and as a lay chalicist at the Washington Cathedral.

"It's obvious that the mouth is a nonsterile organ. . . . a very dirty organ, but it's also capable of coping with a great deal of infection," he said. "That's why people who kiss don't necessarily spread disease."

Dr. Tidball was reluctant to indict the chalice as a disease-spreader since there appears to be no medical literature specifically linking communion with large outbreaks of disease.

"I think that if there were any real risk, we would find something in the literature," he said.

Dr. Droter disagrees. "Monoucleosis has a 45-day incubation period," he says. "Who's to know if you picked it up in church or from the person you're dating?"

Canon Lloyd Casson of the Washington Cathedral recalled, "When I was growing up as a boy, I used to have long arguments with the priest about drinking from the chalice after someone else. It really repelled me.

"He would argue that the women of the altar guilded washed the 'purificators' [the napkins with which the priest wipes the edge of the chalice after each communicant] in something that kills the germs, that because the chalice was silver and smooth without any grooves in it, it would kill the germs. Oh, there's all kinds of lore that's developed."

The Center of Disease Control in Atlanta, however, justifies its criticism of common-cup communion by citing scientists who studied or replicated Anglican communion practices.

A Canadaian study, for example, exploded several of the most common myths:

The silver surface of the cup has virtually no effectiveness as a germ-killer.

The so-called purificators reduced contamination by little more than half.

Even the antibacterial action of the wine's alcohol was found to be ineffective against some disease organisms.

The Canadians, reporting in the Canadian Journal of Public Health, concluded that "both the common cup and its contents could serve as vehicles for the rapid dissemination of infectious microorganisms, and therefore constitute public health hazards."

British investigators reportedly reached similar conclusions.

But Dr. Tidball of GWU says he has reviewed the same literature and concludes that "the gentleman from the CDC expresses more risk than I find in the papers." He is intrigued by the controversy, both as a man of God and a man of science, and declares that "I am going to review the literature and write an article myself."

Medical reports, however, are unlikely to have any effect on the deeply committed, such as Woodard, who made up his mind on the issue long ago.

"I've been a priest for 20 years," he said. "I may be blocking it out of my memory, but I can't say that I've ever had any disease in all that time that I can trace to chalice.

"And I'll go on doing it [drinking from the chalice] no matter what the dentist [Dr. Droter] says -- but I hope he sterilizes his instruments before he works on me!"