Health – for primary school
Treatments that should work in theory often do not work in practice.
An explanation of how or why a treatment may work does not mean it does work, or that it is safe. Even if a treatment does work in a way that it is likely to be helpful, it is not possible to predict how helpful or safe it will be.
For example, cutting someone to make them bleed (bloodletting) used to be a common treatment for lots of problems. People believed it would rid the body of “bad humors”, which is what they thought made people sick. But bloodletting did not help. It even killed people, including George Washington, the first president of the United States. His doctors drained 40% of his blood to treat a sore throat!
A more recent theory was that operating on blocked tubes (arteries) that carry blood to the brain would stop damage to the brain (strokes). That makes sense, but when that theory was tested in a fair comparison, researchers found not only that it did not help, but that some people died from the surgery.
BEWARE if a claim about the effects of a treatment is based only on an explanation of how it works.
REMEMBER: Treatments that should work in theory often do not work in practice.