Monosodium glutamate, or MSG, is glutamic acid, or concentrated salt, used by Chinese cooks to boost the flavor of a dish rather as we use ordinary salt. It is not expensive and keeps indefinitely.
If used well, MSG can do much to improve the flavor of a dish, but it is true that some chefs add too much. In quantity, MSG can cause extreme thirst and other reactions like swollen neck glands, flushes and throbbing headaches. Using salt instead, along with sugar or vinegar is enough to bring out most flavors in food.
Alternatively, use a tablespoon or two of sesame oil or oyster sauce. These are complete seasonings in that they combine salt and flavoring with the richness of the base product. If you add one or both of these, there is no need to use salt, stock cubes or indeed, MSG.
** Asian Online Recipes