In most of the drugs included weight of chemical compounds. Some of them are intended to establish the amount of the drug (such as Vaseline or lanolin oil in ointments) or dilution to the desired concentration. Another part of the substances, which can be found in tablets and solutions – is actually a medicine or active ingredient. It is that substance that has pharmacological effects on organism is required to treatment. Other substances in a preparation may also have any effect, but this effect or not is irrelevant, or the name of a side effect. Active substances in the one drug may be several. Active ingredients are still the name 'International Nonproprietary Name "(INN) drug. Consider an example.

Syrup 'Efferalgan UPSA' contains in its structure many components: paracetamol – The active substance, possessing antipyretic and analgesic effect; inn Efferalgana thus – 'Paracetamol'; flavors providing a sweet taste of the drug, dye, giving the color of the solution, and water – is the basis of the drug, it provides a focus and consistency (thickness). In this case, assigning "Efferalgan", the doctor aims to reduce pain or temperature, and is achieved thanks to the presence of the drug paracetamol. He can come in and into other funds with the same effect, for example, syrup Kalpol "elixir" Tylenol, "" Syrup paracetamol '. All of the above names are called 'trade'. Dyes, flavoring agents, preservatives, thickeners and other ingredients of drugs can cause unwanted side effects, most often – allergies. In addition, if the taste additives used sugar instead of sugar substitutes, it must take into account people with diabetes who have an exchange of sugar in the body is broken. Of course, in most cases, side effects associated yet with the influence of the current the substance of the drug. Synonyms: active ingredient, the active principle, active substance