Medication and toxin-induced neuropathies, although uncommon, are important to identify because of potential reversibility. Numerous medications and toxins are implicated with neuropathy, but objective proof is lacking for many. Chemotherapeutic agents, nucleoside analogs, and other medications and toxins have clear causative links with neuropathy, but many agents have only rare temporal associations. Neuropathies are being recognized from new medications approved for use and other medications, which have expanded indications. Some established associations with neuropathy are less widely known while others are overestimated. Peripheral neuropathy from chronic drug exposure is more problematic to determine. Axonal pathology is most common, but some agents cause demyelination and even conduction block, mimicking immune-mediated neuropathies. Multiple and varied toxic mechanisms are implicated. Neuropathy is a dose-limiting complication of some critical treatments and preventative agents are being actively pursued.