Professor Matthew Chang and Dr Chun-Loong Ho engineered a harmless form of bacteria called E. coli Nissle, which is found in the gut.
Using genetic techniques they developed it into a probiotic that attached to the surface of bowel cancer cells and secreted an enzyme to convert a substance found in broccoli and other cruciferous vegetables into a potent anti-cancer agent.
In tests it killed almost all bowel cancer cells grown in a laboratory.
Then, strikingly, the combination of yoghurt and veg killed 75 percent of tumours in mice with the disease.
The tumours that were detected in the rodents were also three times smaller than in a group not fed the mixture.
The researchers see it being used in two ways - both as prevention and to get rid of remaining cancer cells after surgical removal of tumours.
And one day people may be able to take probiotics as a dietary supplement, along with their broccoli, to ward off the disease, or reduce the risk of it returning.
Interestingly, this mixture had no effect on cells from other types of cancer such as breast and stomach cancer.
The researchers, whose study is published in Nature Biomedical Engineering, said with these special bacteria a dose of broccoli a day can keep the cancer doctor away.
Dr Ho added: "Mothers are right after all, eating vegetables is important."
Colon cancer is the second leading cause of cancer-related deaths in the US, and the third most common cancer in men and women, according to the Centers for Disease Control and Prevention.
Despite its prevalence, it's still unclear what causes colon cancer. However, scientists believe the disease may be linked to western diets, which are typically high in fat and low in fiber.
A 2016 study published in Nature found linked high-fat diets to an increased risk of developing intestinal tumours.
Obesity, red meat alcohol consumption, tobacco use and lack of physical exercise have also been linked to an increased risk of colon cancer, according to the Centers for Disease Control and Prevention.
The US Preventive Services Task Force recommends screening for colon cancer starting at age 50 and continuing to 75.
People with inflammatory bowel disease and/or a family history of colon cancer should get screened earlier.