Acidophilus dosage varies depending on whether you treating an existing disease or taking it for general good health.
Despite what individual manufacturers may indicate, the science of probiotics is still to new for anyone to say with any authority what the standard dose is for Lactobacillus acidophilus or any of the other probiotics. Until very recently we consumed all the Lactobacillus acidophilus we needed in our food and no one suffered from a lack.
One billion cfu (colony forming units) or bacteria should be considered the minimum acceptable dose. Depending on how many are in the supplement you are taking you may need to take several capsules.
What we do know is what has been given to patients in studies to treat or prevent specific disease.
Based on that, to simply maintain current good health, a person can probably get all the acidophilus they need from a diet rich in lactic acid bacteria. That is fermented foods such as yogurt and aged cheeses and fermented vegetables.
To improve your health around 6 - 10 billion cfu each day should be taken. They do not need to all be L acidophilus - it would be sufficient for acidophilus to be part of that mix.
When comparing the effect of different dose rates of Lactobacillus acidophilus it is NOT a case of more is better. Recent studies on animals showed that for some health problems a small amount actually healed better than a high dose rate.
This 2012 study was comparing T cell immune responses to rotavirus vaccination in pigs but the lower dosage gave much better results.
It is still too early to say how this relates to human trials. Just remember, more is not always better.
There is no evidence that L. acidophilus alone will cure yeast infection. There is considerable evidence that Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 can alter the vaginal flora and ensure good health. You can find these two probiotics in Fem-Dophilus. For best result you would treat the yeast infection and then these two should prevent any return - which as you probably know is what it is inclined to do.
Although Acidophilus Pearls are normally recommended for IBS and digestive woes, I see that several of the Amazon reviews for Acidophilus Pearls speak highly of it for preventing yeast infections in women prone to them. Could be worth a try.
And I have heard of a woman eating Activia yogurt (contains Bifidobacterium animalis DN-173 010) curing vaginal discharge. You can read Heather's story on this page of Activia Reviews but I don't know what caused the discharge.