Elephants have enhanced defences against cancer that can prevent tumours forming, say scientists.
A new study warns that a third of all men currently under the age of 20 in China will die prematurely if they do not give up smoking.
A Scottish nurse who contracted Ebola in Sierra Leone last year is in a "serious condition" after being readmitted to an isolation unit in London.
What different countries say about assisted dying
A look at the work that won this year's Nobel Prize in medicine
How can scientists 'cure' blindness?
Why is the NHS short of some key drugs?
On Pingelap, a tenth of the population is totally colour-blind.
Who decides what's fair when it comes to putting a price on life-saving medicines?
How safe is the air that we breathe?