Viagra could boost cancer survival rates.
The drug is commonly used to treat men with erectile dysfunction but researchers have found that the little blue pill could hold some important clues in attempts to beat cancer.
Scientists have discovered that phosphodiesterase type 5 (PDE5), a chemical found in Viagra, can shrink tumours found in the oesophagus and can even make chemotherapy more effective in those who are resistant to the treatment.
Experts from the University of Southampton tested the drugs on mice with promising results and are now hoping to start human trials soon.
Michelle Mitchell, chief executive of Cancer Research UK, said: "Developing new drugs for cancer is incredibly important, but doing so from scratch is a challenging process, and many fail along the way.
"We've also been keen to explore whether existing drugs, licensed for other diseases, can be effective in treating cancer.
"If these turn out to be successful treatments, they will also prove to be more affordable and become available to patients quicker."