<unk> s can generally be classified by the following characteristics:
re-labeled drugs that were previously expired, defective or otherwise deemed unfit for use;
re-labeled drugs wherein the active ingredient is fraudulently diluted;
re-labeled drugs wherein the active ingredient is adulterated;
re-labeled drugs wherein the active ingredient is substituted;
falsely-labeled substances of any composition wherein the active ingredient is completely misrepresented; and
falsely-labeled substances whose combined active ingredients meet one or more of the preceding criteria.
An individual who applies a<unk>  medication may experience a number of dangerous consequences to their health, such as unexpected side effects, allergic reactions, or a worsening of their medical condition. A number of<unk> s do not contain any active ingredients, and instead contain inert substances, which do not provide the patient any treatment benefits.<unk>  medications may also contain incorrect ingredients, improper dosages of the correct ingredients, or they may contain hazardous ingredients.
The extent of the problem of<unk> s is unknown.<unk> ing is difficult to detect, investigate, and quantify. So, it is hard to know or even estimate the true extent of the problem. What is known is that they occur worldwide and are more prevalent in developing countries. It is estimated that upwards of 10% of drugs worldwide are<unk> , and in some countries more than 50% of the drug supply is made up of<unk> s. Furthermore, the World Health Organization estimates that the annual earnings of<unk> s are over US$32 billion  .
There are several technologies that may prove helpful in combating this problem, such as radio frequency identification which uses electronic devices to track and identify items, such as pharmaceutical products, by assigning individual serial numbers to the containers holding each product. The FDA is working towards an Electronic pedigree (ePedigree) system to track drugs from factory to pharmacy. This technology may prevent the diversion or<unk> ing of drugs by allowing wholesalers and pharmacists to determine the identity and dosage of individual products.
Some techniques, such as Raman spectroscopy and Energy Dispersive X-Ray Diffraction (EDXRD) can be used to discover<unk> s while still inside their packaging.
Counterfeit drug
Marine toxins
Hazardous drugs
Food additive
Pesticide
Designer drug
Generic drug
Off-label use