For many years doctors have been aware that smoking affects men and women in different ways.
Recently, they say, there has been a surge in the number of cases of colon cancer. Now a team of Norwegian researchers says women smokers are specifically at risk.
The researchers looked into the medical histories of more than 600,000 people over the course of 30 years.
So far doctors cannot explain why smoking seems to attack the female digestive system more aggressively than the male.
One leading cancer specialist says this new research is a warning to women.
Al Jazeera's Dominic Kane explains.