Some people find they need 1000mg per meal to start, then can reduce the dose to 500mg per meal after 2 weeks. If 2 pills (1000mg) makes you constipated, try drinking a few ounces of aloe vera juice with it.
Probiotics are the beneficial bacteria in our intestines that we are born with. Acidophilus, bifidus, etc. Antibiotics kills them. Stress also depletes them. They help keep stool softer and well formed for better relularity. Some people find a reduction in odours from taking probiotics. Others find it makes it worse. It's all an experiment. They boost the immune system and help prevent food poisoning and candida overgrowth.