Professor Robert Winston has raised concerns over a partnership between Amazon and the NHS.
Amazon's Alexa device will now answer any health questions with information from the NHS website, which has been verified by professionals.
But Professor Winston told talkRADIO’s Matthew Wright patients want “face-to-face contact with a doctor”.
“Alexa isn’t listening to us. She’s recording what we say and it’s going to somewhere in some other part we have no control over that information whatsoever,” he said.
“There is an element of these technologies which is really quite sinister and Alexa cannot be the way to practice medicine.”
Health Secretary Matt Hancock has called the partnership “absolutely terrific” and said it will reduce pressure on GPs and pharmacists.
However Professor Winston said the health system is no longer training doctors to “sit and just listen to what the patients are telling them”.
“Unfortunately increasingly they’re getting more conversations and more consultations over a telephone or over Skype. On the whole I don’t believe that can lead to as good medicine as actually having that human contact,” he said.
“Actually having trust and faith and belief in somebody who’s actually clearly concerned about you is really a very important part of the healing process.”
Amazon has sought to allay concerns from privacy groups that it cannot be trusted with such sensitive data.
It said “customer trust is of the utmost importance”, and it has pledged not to share any health information with third parties.