The toll carriageways were closed in both directions after a member of the public reported someone on a Megabus pouring a liquid into a bag causing smoke or fumes.
"The information received concerned a report of vapour escaping from a bag which on investigation turned out to be a health improvement aid for smokers," a Staffordshire police spokeswoman said.
An earlier force statement read: "At around 8.20am today we received a report from a genuinely concerned member of the public about suspicious activity on a coach travelling on the M6 toll at Weeford, near Lichfield.
"Staffordshire Police coordinated a multi-agency response. Given the nature of the report we responded swiftly and proportionately, treating the information as credible and extremely seriously."
It continued: "Following an initial assessment, we can confirm that no-one has been injured and that there is no danger to passengers at the scene or any other travellers who were on the motorway at that time.
"We are also not treating anyone as a suspect... Importantly, we are not treating this as a counter-terrorism incident."
Watch BBC video footage of the incident below