A magic-mushroom compound blocks a severe side effect of chemotherapy, in mice

One of chemotherapy's cruellest side effects rarely makes headlines because its name is a mouthful: peripheral neuropathy. As the drug kills the tumour it also strikes the nerves in the hands and feet, leaving numbness and a burning ache that can last for years and often forces oncologists to lower the dose. A team at the MD Anderson Cancer Center in Houston found a protector by accident: a colleague noticed that mice given psilocybin for an unrelated experiment never developed neuropathy.

Tested properly, two doses before chemotherapy kept the mice fully protected through as many as six treatment cycles. Given after the damage started, psilocybin cut the hypersensitivity to about three months. The mechanism is a transport system inside the nerve.

Chemotherapy wrecks the microtubule "rails" that carry energy-making mitochondria along the axon, so the far end of the nerve starves. Psilocybin keeps that railway running — an effect seen in both mouse and human nerve cells in the dish. This is still mice and cells, but MD Anderson plans a phase 2 trial in about 80 patients on chemotherapy for breast, colorectal, or head and neck cancer.

A drug studied for twenty years as a psychiatric treatment turns up here as a nerve guardian. Source: Nature, nature.com/articles/d41586-026-02744-6 (study: Heles et al., Science, 2026).