Doctor's Best Calm with Zebrine helps combat stress, tension, and occasional anxiety. It helps increase attention, focus, motivation, and concentration. Zebrine is a patented standardized extract of selenium tortuosum; its use has been documented for more than 300 years. It has been clinically shown to enhance cognitive function and is cultivated in an environmentally stable process. Dr. Nigel gericke is a medical doctor, and an ethno-botanist. He has studied the use of botanicals by indigenuous people throughout he world. In South Africa, he was amazed by the conversations he had with the nomadic San people living in the deserts. Eighty and ninety year old men and women were able to have very lengthy and Lucid conversations with him, and when he studied some of their habits, he realized that they were picking and chewing the leaves of the selenium tortuosm plant. This LED to the beginning of his studies on what would ultimately become a highly standardized extract of the botanical, Zebrine.