Lactobacilli is beneficial in the intestinal tract and also vagina therefore aiding against vaginitis too.
But, as known, lactobacilli doesn't get into the bloodstream which limits its capacity to the bowels and the vagina.
So if you have candida that has gotten into the bloodstream probiotics are only useful for a healthy bowel movement.
An overuse of probiotics may only result in excessive drainage symptom and shows in the form of headache, diarrhea, bloating and constipation.
Allergic reactions against probiotics may occur but not specifically against lactobacilli since their composition with other compounds vary from product to product.
Ps. Pregnant women and nursing mothers should only use probiotic nutritional supplements if recommended by their physicians Ds.