Probiotics are a source of good bacteria which alter the intestinal microflora balance and support digestion and immune balance.They also prevent or reduce the growth of harmful bacteria. The lactobacillus and bifidobacteria help to maintain a healthy intestinal flora through the production of certain organic compounds such as lactic acid, acetic acid and hydrogen peroxide.These compounds alter the pH by increasing the acidity of the intestine and inhibit reproduction of harmful bacteria. Probiotic bacteria also produce bacteriocins which help by killing undesireable organisms.

The dose required for these organisms is dependant upon the amount of friendly bacterial depletion and the presence of harmful bacteria. Normally 1 to 2 billion colony forming units (CFU's) is considered to be the minimum dose for maintenance of a healthy intestine .

Probiotics are present in some yoghurts to a varying degree, but not to the same extent as you obtains from supplementation with probiotics.Many frozen yoghurts do not contain any or have very little live bacteria. Probiotics come in either heat stable forms, meaning they can be safely stored in normal room temperature, and heat intolerant forms, meaning they need to be stored long term in a cool environment in the fridge. These supplements come in capsule, tablet and powder forms.