LONDON — “Alexa, how do I treat a migraine?”

When British users ask Amazon’s voice assistant system for medical advice, it can respond as of Wednesday with the authority of an organization once described as “the closest thing the English have to a religion”: the country’s National Health Service.

The collaboration, described by Britain’s Department of Health and Social Care as a world first, has prompted immediate questions about medical privacy, and about the propriety of a state-run service forming a partnership with an overseas technology corporation.

Health advice from Alexa is not new — Amazon has worked with the American medical site WebMD since 2017 — but this time it represents a connection with a universal state health service, revered even as it creaks under the strain of tight budgets and an aging population.

The British health secretary, Matt Hancock, said Alexa could help reduce strain on doctors and pharmacists. “We want to empower every patient to take better control of their health care,” he said in a statement, “and technology like this is a great example of how people can access reliable, world-leading N.H.S. advice from the comfort of their home.”