Edible vaccines made from plants? This seemingly unusual proposition is on the verge of becoming a reality. Preliminary studies in the US indicate that genetically altered potatoes, bananas, alfalfa sprouts and other foods could revolutionize medical care by providing cheap and plentiful sources of "edible" vaccines and other medicines to safeguard against many diseases.

In an experiment carried out at the Texas A & M University in Houston, mice fed on genetically-engineered potatoes produced antibodies against a bacterium responsible for diarrhoeal disease. "This is the 1st time we've shown that giving material orally in the form of a food can stimulate an immune response," says Hugh Mason, a research assistant professor at the University.