Acidophilus is often composed of several bacteria strains that are good for digestion. It is sold in liquid or in capsule form (no tablets that need to be crushed). If you look for this product look for one that is kept cold. Some places keep it on the shelf which supposedly doesn't allow the bacteria to live as long.
Acidophilus can help get rid of green stools in hedgehogs, but it also is thought to have many other properties. Like it helps with digestion, helps boost the immune system, it helps produce the chemicals that aid in digestion.
Have you ever had a "tummy upset" and was told to eat yogurt? The reason yogurt can make you feel better is often due to the good bacteria it contains.
As for how much... well I use very scientific methods. Small pinch, large pinch, 1/2 capsule... How much will depend on why I'm giving it. I'll sprinkle a small pinch on my hedgehog's food if their stool looks to be a little off (say from a new food I gave them). For hedgehogs that are on antibiotics, I give a larger pinch amount. And for those that are being syringe fed (these are often cancer patients) I will increase it to half the capsule a day.
Someone may do it a little differently, but this is what I do.
