Which health treatments and devices have been promoted without strong evidence of usefulness?

Quackery involves the promotion of health treatments and devices that lack scientific evidence of efficacy, often driven by financial gain and the exploitation of public fear or vanity. Charlatans frequently capitalize on new scientific discoveries, using exaggerated claims to sell products that are ineffective or potentially harmful.1

Historically and currently, various methods have been promoted without strong evidence of usefulness, including:

• Devices: Examples include Elisha Perkins’s "metallic tractors" (brass and iron rods claimed to draw disease from the body) and various "magical" magnetic belts, lights, and complicated machines of no particular merit.1
• Nostrums and Drugs: Many preparations have been marketed as cures for serious conditions like cancer, tuberculosis, and syphilis. These often contained little more than bitter herbs, salt, sulfur, or alcohol, and later, aspirin.1
• Radioactive Products: Following the discovery of radium, some products claimed to contain the substance, leading to severe health consequences for users.1
• Cosmetic and Lifestyle Claims: Vitamins have been incorporated into products for hair growth or preventing grayness without evidence of efficacy, and various preparations have been sold for rejuvenation and sexual power.1
• Alternative Practices: Methods such as homeopathy and the manipulation of bones, muscles, and tendons have also been vaunted as useful in controlling disease despite a lack of rigorous validation.1