Labels marked "tested on animals" should be placed on medicines to educate users about the value of scientific research, a Lib Dem MP says.
The pharmaceutical industry fears people's health could be put at risk
Evan Harris, a former hospital doctor, says he believes the tags would counter the claims of animal rights protesters.
The pharmaceutical industry says this could put people off taking medicine.
The British Union for the Abolition of Vivisection (BUAV) says the move would only confuse people and would not prove animal tests were needed.
The debate follows Tony Blair's pledge to sign an online petition which backs animal testing.
The prime minister, who condemned the "appalling" actions of animal rights extremists, will join around 13,000 people on the People's Petition.
Dr Harris, MP for Oxford West and Abingdon, told BBC Radio 4's Today programme it was important to demonstrate to consumers the "significant benefits" to them from animal testing.
"On the whole animal rights issue, we are very complacent," he said.
"We get a few convictions of extremists and we have a few people marching in Oxford against extremists and we think we are winning the battle.
"We are not winning the battle for hearts and minds, particularly of young people.
"It's important that we make it absolutely clear that there are significant benefits to individuals from animal testing.
"The most obvious way is at the point of use of the end result of that animal research, in the health service.
"Putting a label on saying this medicine has only been made available through insights gained in its development and safety-testing through the humane use of animals is necessary in order to educate people and win the battle."
However, Philip Wright, of the Association for the British Pharmaceutical Industry, said he feared the move could have a harmful impact on health.
"We are concerned that somebody, for example, who has taken an asthma medicine each day may decide to stop taking it and that might lead to a life-threatening situation," he told Today.
He added that there were also practical problems with finding space for a "tested on animals" stamp on crowded medicine labels.
Alistair Currie, campaigns director for BUAV, said he believed the public should be better informed, but argued that labelling medicines "tested on animals" would just be a statement of fact.
"I think that would be misleading to the public as all medicines are tested on animals - that does not mean they have to be tested on animals," he said.
"It is just propaganda for animal testing - it's not helping the public to understand the issue better.
"It may make people feel 'oh, that means we have to have animal testing', which we don't."
Mr Currie said a large number of medicines that passed animal tests, failed human tests, but this was rarely reported.