The placebo effect can be incredibly powerful, performing nearly as well as carefully designed and tested drugs, substituting for actual surgeries and even generating side effects. But it’s a tricky thing to apply outside of experiments. After all, not everyone will have a strong placebo response, so it’s unethical to use it in place of actual treatments.

Now, some researchers in Germany have figured out a way to harness the placebo effect to increase the impact of a normal drug treatment. The procedure involves getting patients to associate a taste with a powerful drug that has problematic side effects. Once the association is made, the patients were given a mix of normal drugs and a placebo, along with the flavor they’d associated with the drug. This experiment enhanced their response to the drug, providing an avenue to potentially reduce its dose and, thus, its side effects. And the whole thing worked despite the fact that the patients knew exactly what was going on.

The drug at issue, cyclosporine A, is a powerful suppressor of the immune system, which makes it useful for patients who have received organ transplants or who have a strong autoimmune disorder. But the immune system isn’t the only system affected by this drug; it also kills off kidney and nerve cells and causes heart problems and hypertension. These effects are independent of any changes to the immune system, but nobody has figured out a way to target the body’s response specifically to immune cells. As a result, people taking this drug have to carefully balance its useful features against its toxicity.