All 19 Lib Dem MPs abstained on the motion by Labour leader Jeremy Corbyn in Parliament.
Every other party voted for the motion apart from the Lib Dems and the Tories, the latter voted against it.
Mr Corbyn called on MPs to back the idea of all NHS services being brought back entirely into public hands and to fully protect the NHS from all aspects of future post-Brexit trade agreements.
Labour were joined by the SNP, Plaid Cymru and the Green Party in backing the move.
The Conservatives voted against it and the bid lost by 310 votes to 282 votes.
Afterwards, Mr Corbyn tweeted: “The Tories just voted against Labour’s motion to safeguard our NHS from being sold off to US corporations in a Johnson-Trump trade deal. And the @LibDems, who voted to privatise the NHS when in coalition, abstained.”
While Labour MP Jonathan Ashforth said: “Tory MPs have refused to safeguard the NHS from a Trump deal sell off that locks in privatisation.
“The actions of Tory MPs and inaction of Lib Dems who abstained, risks further privatisation of our health system and could open the door to US pharma forcing our NHS into buying more expensive medicines.”
Local SNP politicians also hit out.
SNP prospective parliamentary candidate for East Dunbartonshire, Amy Callaghan, said: “This is another example in a long list of Jo Swinson and the Liberal Democrats selling out the people of Scotland.
“Our NHS is too precious to barter with or include in any trade agreement. The SNP have consistently protected our NHS and I will continue to do so if elected as your MP.
“Jo Swinson and the Lib Dems should hang their heads in shame.”
While Milngavie SNP MSP Gil Paterson said: “This lack of commitment by Jo Swinson and her party to the principle of a publicly funded and run NHS is completely irresponsible and this lost vote will also have very damaging ramifications on Scotland’s NHS.”
He added: “Although health is a devolved power in Scotland the Scottish Government will be unable to resist the creeping privatisation this UK legislation has unleashed, because funding and trading powers are held by Westminster.”
“Already there are two very different reported private spending amounts in the NHS in England & Wales. On the one hand the Dept. of Health & Social Care’s accounts show that 7% of expenditure is on “independent sector providers” whilst the Centre for Health & Public Interest put the figure at an enormous 26%. Either way these figures will pale to insignificance if the Tories get their way on unfettered trade deals which include public health services.
“Jo Swinson and her Liberal Democrat colleagues should be ashamed of themselves on this issue which will see Scottish public health services put in jeopardy.
“The Scottish Health Service is funded pro-rata on the basis of what is spent on the NHS in England, therefore the more that is privatised in England, the less there is to spend when the Scottish Block Grant is cut accordingly”.
The Herald contacted Lib Dem leader Jo Swinson’s office this morning (Thursday) and is awaiting a response.
However, in response to criticism, Caron Lindsay wrote on the Liberal Democratic Voice website: “We have good form on the NHS and trade deals.
“For a start, we have on very many occasions challenged the government on exactly this point. We do not want to see the NHS undermined by Donald Trump.”