An Italian woman who received death threats after declaring in an internet posting that she owed her life to medicines developed from testing on laboratory mice has been admitted to hospital with a severe lung infection.

Caterina Simonsen, 25, last week appeared on Italian national television to answer abuse from animal rights militants who took exception to her Facebook post in which she defended the use of testing on animals for medical purposes.

In that post on December 21, she uploaded a photo of herself with a message: "I am 25 thanks to genuine research that includes experiments on animals.

"Without research, I would have been dead at nine. You have gifted me a future."