Opponents of quackery have suggested several reasons why quackery is accepted by patients in spite of its lack of effectiveness:
Ignorance: Those who perpetuate quackery may do so to take advantage of ignorance about conventional medical treatments versus alternative treatments.
The placebo effect. Medicines or treatments known to have no effect on a disease can still affect a people's perception of their illness. People report reduced pain, increased well-being, improvement, or even total alleviation of symptoms. For some, the presence of a caring practitioner and the dispensation of medicine is curative in itself.
Side effects from mainstream medical treatments. A great variety of pharmaceutical medications can have very distressing side effects, and many people fear surgery and its consequences, so they may opt to shy away from these mainstream treatments.
Distrust of conventional medicine. Many people, for various reasons, have a distrust of conventional medicines (or of the regulating organizations themselves such as the FDA or the major drug corporations), and find that alternative treatments are more trustworthy.
Cost. There are some people who simply cannot afford conventional treatment, and seek out a cheaper alternative. Nonconventional practitioners can often dispense treatment, which may be unproven, at a much lower cost.
Desperation on the part of people with a serious or terminal disease, or who have been told by their practitioner that their condition is "untreatable". These people may seek out treatment, disregarding the availability of scientific proof for its effectiveness.
Pride. Once a person has endorsed or defended a cure, or invested time and money in it, they may be reluctant to admit its ineffectiveness, and therefore recommend the cure that did not work for them to others.
Fraud. Some practitioners, fully aware of the ineffectiveness of their medicine, may intentionally produce fraudulent scientific studies and medical test results, thereby confusing any potentional consumers as to the effectiveness of the medical treatment.
Coincidence Certain "self-limiting conditions", such as warts and the common cold, almost always improve, in the latter case in a rather predictable amount of time. A patient may associate the usage of alternative treatments with recovering, when recovery was inevitable.