What is the difference between probiotics and prebiotics?

Probiotics are living microorganisms which, if they are prescribed in sufficient quantity, render positive effect on human health.

Probiotics supplements may increase in comparatively short time the quantity of beneficial bacteria in the intestine, which is important, for example, after course of antibiotics. But the effect doesn’t last long.

Experiments show that integration of bacteria leads to a change of the microflora composition for a short period of time, then the primary composition restores soon. It’s necessary to mention that some compositions of probiotics may have a negative impact on human health. That’s why it is very important to consult doctor before taking them.

As living organisms, probiotics:

• Not always survive in the intestine;
• Are exposed to negative influence of antibiotics;
• Don’t live long in the intestine (approximately 5-7 days);
• May induce resistance to antibiotics to pathogenic strains of the human microflora.

Prebiotics can render more influence on microflora than probiotics because:

• They cannot be destroyed in the digestive tract and are not exposed to negative influence of antibiotics and acidic conditions of the stomach;
• They stimulate the growth and evolution of own strains of various human beneficial bacteria;
• Don’t cause secondary immune response;
• Don’t bear genes of resistance to antibiotics.

Источник (Reference)
R. Walker, M. Buckley.Probiotic microbes: the scientific basis.A report from the American Academy of Microbiology, 2006.