TORONTO — As medical research goes, it doesn't seem the most pleasant of pursuits -- rummaging through snippets of people's intestines and bits of stool to ferret out microbes.

But for a group of Canadian and U.S. researchers, exploring what most of us would rather not think about has yielded a potential bonanza of information about the bacterial contents of the human gut, a first step in figuring out what role these bugs play in keeping us healthy or making us sick.

Using samples of colon tissue from three healthy people in Manitoba, the researchers set out to catalogue all the different species of bacteria by looking at their genetic makeup.

Many of these microbes were already known to colonize the large intestine. But what fascinated the scientists was the number that had never been seen before -- and the fact that each person seems to have their own unique mix of bugs.

"Over 60 per cent of what we found was novel, meaning that they were not described before," said Dr. Paul Eckburg, an infectious disease expert at Stanford University. "We know the broad class, but we don't know their species names or their functions. They're completely new and undiscovered.

"We were overwhelmed and little bit surprised that we were seeing so many novel species," Eckburg said Thursday from California.

Their study, appearing in this week's issue of Science, is part of an ongoing collaboration that began with Dr. Charles Bernstein, a gastroenterologist at the University of Manitoba, who provided the tissue and stool samples to Stanford for genetic analysis. Other U.S. researchers are also participating.

"We probably only understand about 20 per cent of the species that are present in the bowel," Bernstein, head of the university's centre for inflammatory bowel disease, said from Winnipeg.

"There are more bugs in the gut of humans than cells in the body," he said, noting that they number in the many trillions. "And although typically we think of bacteria as being bad things, there are many, many bugs in the bowel that are good bacteria, and in fact, we need to have that balance to keep the bowel in check and to fend off bad bacteria."

While the discovery of so many unknown microbial species is exciting, it is just a first step in the ultimate purpose of the research -- to help people with Crohn's disease and ulcerative colitis by seeing if what's in their guts may be causing their illness.

Canada, where the diseases affect about 170,000 people, is one of the world's hotspots for inflammatory bowel disease, although experts don't know why.

Symptoms of Crohn's disease include abdominal pain, fever, vomiting, weight loss, diarrhea, and sometimes gastrointestinal bleeding. It is treated with anti-inflammatory drugs; surgery is successful only in a few cases.

Ulcerative colitis is an inflammation of the colon and rectum. Symptoms include abdominal pain and bloody diarrhea. Drugs and surgery are also used in treatment.

Bernstein said further studies will compare the typical soup of microbes in the colons of healthy people with those in people with inflammatory bowel disease, or IBD.

"If we actually define that there's a certain species of bug that's more prevalent or only present in Crohn's disease or ulcerative colitis and wasn't prevalent or not even present in healthy (people), then we might have a clue that maybe this bug is really important in the cause of the disease.

"And maybe if we find an antibiotic or other therapy that can eradicate or suppress that bug, perhaps that will affect the course of the disease."