I purchased Demal 200 in preparation for a trip to Nairobi, Kenya, but soon after arriving learned that there was no threat of getting malaria, so I stopped taking it. During the first week there, other members of my team began coming down with strep throat and other ailments. At times in the evening I would feel as though the symptoms of something were coming on and I would take two squirts of the Demal 200 because I knew it boosted the immune system and thought it might help. Each time I took it, I felt fine in the morning and I never came down with any sickness. I don't know if it was the Demal 200 that helped me to feel well, but I don't doubt it. Thanks!