The properties and functions of 35 vitamins will be investigated. All these vitamins participate in functioning of various bodies and systems of organism. However, to a number of the most known vitamins concern vitamins A, A1, A2, A6, B12, PP, H, C, D, K, F, E and folic acid. These vitamins concern a number of the most widespread and used in medicine. However, so that the organism could receive a recommended daily doze of all vitamins with food, it is necessary to eat rather a plenty of greens, fresh vegetables and fruit, meat, eggs and milk every day.

However, 90 % of the food used by modern people is exposed to long temperature processing. When foods are boiled or cooked at high temperatures they lose their nutritional content. After just 30 minutes in an oven; the food retains less than 30 % of its vitamins. Thus, owing to the lack of natural vitamins of human daily ration doctors recommend to use complex vitamin preparations, in which structure some of different vitamins in a view of their compatibility and synergistic are included.

The structure of majority of vitamin complexes contains synthetic vitamin. Synthetic vitamins are received with the help of complex chemical reactions. As initial components to reception of synthetic vitamin aromatic hydrocarbons, benzene and his derivatives, polysaccharide and spirits can be applied. Synthetic vitamin cost is defined in a view of raw material cost, charges on transportation, manufacture and realization. However, the "know-how" of synthetic vitamin is in most cases much easier than technology of vitamins extraction from vegetative or animal raw material. Thus, synthetic vitamin cost is more often lower than the cost of natural vitamins. Besides, according to some data, comprehensibility of natural vitamins is much higher than comprehensibility of synthetic vitamin.

Nevertheless, there are some chemical vitamin advantages. To a number of the basic chemical vitamin advantages concern: the absence of by-effects and the opportunity to combine different vitamins and their derivatives. Besides, one of the basic differences of synthetic vitamin is potentially a low ability to collect in bodies and tissue. The majority of synthetic vitamins decays easily and deduced from organism through sudorific gland and urinary tracts.

Nevertheless, synthetic vitamins don't contain everything. High allergenic ability concerns to one of the most essential lacks. At the use of vitamin complexes in which structure natural vitamins are included, there is a certain risk of allergic reaction occurrence. Whereas at reception of vitaminized additives or vitamin complexes, in structure of which there are synthetic vitamins, the risk of allergic reactions occurrence grows in 1,5 times.

However, for prevention of allergic reactions occurrence at the use of synthetic vitamin it is recommended to consult the doctor and precisely to observe a dosage of preparation. It is necessary to note that the excess of recommended doze of vitamins is one of factors which can provoke the occurrence of allergic reaction.