A completely different take on this phrase is that discretion means being discrete as in protecting people or information from exposure in some manner. If one is to be perceived as possessing valor by others, then they cannot express this by being merely brash and powerful.
Probiotics are essential (for at least a month or two after the antibiotics stop, depending on the potency) when you have had antibiotics to replenish the beneficial bacteria.
As a matter of fact, there are already probiotics present in your body. The majority of these bacteria reside in your digestive system. The point of probiotics is simply to increase the number of good bacteria and to diversify the types of beneficial bacteria. It is estimated that the bacteria that coexist with our bodies outnumber our bodily cells by three to ten times.