So glad to find the 4,000 ppm strength. My husband has MRSA and recently had an open wound that would not heal. It still needs more healing but is showing improvement. Halleluyah! We are giving him 2 drops internally every 6 hours and mixing 2 drops per 2 tsp. bentonite clay and 1/2 oz. water. Mix together and apply to wound and cover with non-stick pad. We change it every 6 hours. Peel off the pad and the clay or rinse off with lukewarm water. Let air-dry one hour and re-apply the clay and non stick pad. Repeat until well.