Quackery is also involved in misleading advertising of dietary supplements, homoeopathic products, ayurvedic medicines and some non-prescription drugs. In many such instances no individual 'quack' is involved - just deception by manufacturers and their advertising agencies.
Some products can be useful for some purposes, but worthless for others.
For example, vitamin B 12 shots can be life-saving in cases of pernicious anemia, but giving them to 'pep you up' is a form of medical fraud. While there is no doubt that homoeopathic medicines can be helpful, the concept of a standard homoeopathic remedy for common illnesses such as headaches and colds flouts a basic homoeopathic principle, which states that remedies need to be tailor made for a particular person and only a skilled homoeopathic physician can identify the required medicines properly. Unproven methods are not necessarily quackery. Those consistent with scientific concepts may be considered to be experimental, but legitimate practitioners do not go around promoting unproven procedures in the marketplace. Instead, they engage in responsible, properly designed research studies to prove or disprove their claims.