NHS Lothian is investigating allegations that the staff consumed alcohol during their shifts at the Western General in Edinburgh on New Year's Day.
The porters' roles do not involve any contact with patients.
George Curley, director of operations - facilities at NHS Lothian, said: "We are investigating allegations into a small number of portering staff drinking alcohol whilst on duty at the Western General Hospital on Wednesday, January 1.
"NHS Lothian takes any instances of this nature extremely seriously and, as a result of this incident, six members of staff have been suspended and a full investigation is under way.
"These suspensions had no impact on patients within the hospital and the work of the individuals involved was carried out by other colleagues."