What term best describes a deceitful remedy?

The term "nostrum" specifically refers to a dubious or unproven remedy, often characterized by its deceitful nature or the lack of scientific evidence supporting its efficacy. Historically, nostrums have been associated with quack medicine, where sellers promote unverified treatments as cures for various ailments, despite little or no actual medicinal value.

In contrast, "pharmaceutical" refers to drugs and medications developed through rigorous scientific research and clinical trials, aimed at ensuring safety and effectiveness. "Legitimate" describes something that is lawful and credible, which does not align with the context of a deceitful remedy. Meanwhile, "concoction" generally refers to a mixture or blend of different substances, which can be benign, harmless, or even beneficial, but does not inherently convey the deceitful implications suggested by the question.

Thus, the most appropriate choice that captures the essence of a deceitful remedy is "nostrum."