Dear Dr. Roach: What’s the difference between homeopathy and allopathic medicine? — H.L.

Answer: Homeopathy is a pseudoscience based on two assumptions. The first is that the body always knows what to do, so treatment includes a substance that will cause the same symptom a sick person currently has in a healthy person. This seems like a reasonable hypothesis, and it is right some of the time, but not all of the time. For instance, in a person with heat stroke, it’s not a good idea to give a substance that causes a fever.

The second assumption in homeopathy is that the less of a substance you give, the more effective it is.

Homeopathy was founded around 1796, before atoms and molecules were understood. Most homeopathic remedies don’t contain a single molecule of the active substance, so even when a useful treatment is given, it is usually given at a dose so low that it shouldn’t be effective. The Food and Drug Administration has not approved any homeopathic preparations or products.

Many people confuse herbal medicine with homeopathy. They are not alike. Much of the pharmacopeia is based on herbal medicine, and for many conditions, herbal medicines are sometimes a valid alternative, if they aren’t the current treatment.

The term “allopathy” was not used by the regular doctors of the time, and we shouldn’t use it to describe today’s medical doctors.

It was coined by the homeopaths in an attempt to create a kind of false equality between regular medicine and homeopathy. “Allopathy” comes from the Greek root word meaning “opposite feeling.” So, going along with the previous example, an allopath might cool down the patient suffering from heat stroke. While allopathy, too, is a reasonable place to generate a hypothesis, treatments with allopathic properties are not always effective.

What really distinguishes modern medicine from homeopathy is science. Allopathy versus homeopathy is a false choice.

The real choice is between a system based on questionable assumptions and a system based on the scientific method.