Processed meats - such as bacon, sausages and ham - do cause cancer, according to the World Health Organization (WHO).
Its report said 50g of processed meat a day - less than two slices of bacon - increased the chance of developing colorectal cancer by 18%.
Meanwhile, it said red meats were "probably carcinogenic" but there was limited evidence.
But the WHO said meat did also have health benefits.
Processed meat is meat that has been modified to increase its shelf-life or alter its taste - such as by smoking, curing or adding salt or preservatives.
It is these additions which could be increasing the risk of cancer.
The WHO has come to the conclusion on the advice of its International Agency for Research on Cancer, which assesses the best available scientific evidence.
It has now placed processed meat in the same category as plutonium, but also alcohol as they definitely do cause cancer.
However, that is not an indication of how much cancer they cause. It does not mean eating a bacon sandwich is as bad as smoking.
"For an individual, the risk of developing colorectal (bowel) cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed," Dr Kurt Straif from the WHO said.