The sickening gardening habits of medieval monks left them more infested with parasitic worms than the general population, archeologists say.

A new analysis of the 12th-14th century skeletons of an Augustinian monk in Cambridge has found that six in 10 monks were infected with intestinal worms, compared with around a third of the city’s population.

Researchers from the University of Cambridge’s Department of Archeology believe the difference in infection rates may be due to monks growing crops in the friary gardens with their faeces, or using fertilizer containing human or pig faeces.

Experts said they were surprised by the findings because monasteries are more hygienic than the homes of ordinary working people, often with running water toilet blocks and hand-washing stations instead of communal waste.

Dr Piers Mitchell, lead author of the study, said: “This is the first time anyone has tried to find out how common parasites were in people living different lifestyles in the same medieval city.”

“Medieval Cambridge monks appear to be full of parasites.”

Augustinian Friary with additional parasites

Cambridge archaeologists examined soil samples taken from the former All Saints cemetery by the Castle Church, as well as from around the urns of adult remains from the area that once housed the city’s Augustinian Friary.

The friary at Cambridge was an international house of study, and clergy from all over Britain and Europe came to read the manuscripts.

It was founded in the 1280s and lasted until 1538 before being destroyed as part of Henry VIII’s break with the Church of Rome.

While the 32 percent prevalence of parasites in the urban population is consistent with studies of medieval burials in other European countries, friary rates were found to be remarkably high.

The study suggests that the actual number of infections may be higher, but some traces of worm eggs in the pelvic sediment would have been destroyed by fungi and insects over time.

Wormwood and powdered moles

“Roundworm was the most common infection, but we also found evidence for whipworm infection,” said researcher Tianyi Wang, who performed microscopy to detect parasite eggs.

Because roundworms and whipworms spread in poor sanitation, the researchers argue that the difference in infection rates between priests and the general population must be related to how each group handles human waste.

“One possibility is that the monks fertilized their gardens with human excrement, which was not uncommon in the Middle Ages, and this may have led to reinfestation of the worms,” ​​Mitchell said.

Medical books written around the same time by Cambridge physicians mentioned worms, but thought they arose from phlegm or mucus rather than poor hygiene. Treatments include aloe or wormwood, and even grinding moles into powder to make a medicinal drink.

The study was published Friday in the International Journal of Paleopathology.