Study	Reason for exclusion
Ackerhans 1994	Participants had acute rhinitis
Anderson 1956	Not a RCT
Anonymous 1975	Not a RCT
Ashe 1968	Participants had nasal obstruction due to various reasons including allergy
Bailey 1969	Participants had nasal obstruction due to various reasons including allergy
Bende 1984	Participants had nasal obstruction, not due to common cold
Bende 1985	Nasal stuffiness was the only inclusion criterion, hence it is not clear for how long participants experienced nasal congestion and whether this was due to the common cold
Broms 1982	Participants suffered from nasal obstruction for more than 6 months
Castellano 2002	Participants had reduced airflow, which was not necessarily due to the common cold
Cohen 1977	Combination therapy
Connell 1969	Some of the patients had allergic rhinitis
De Paula Neves 1966	Combination therapy
Dorn 2003	Trial was not placebo‐controlled
Fox 1967	Trial was not placebo‐controlled
Hummel 1998	None of pre‐specified outcome measures were reported
Katrana 1956	Not a RCT
McElhenney 1966	Not a RCT
Meurman 1975	Trial was not placebo‐controlled
Pritchard 2014	Participants with hay fever were also included
Rumiantsev 1993	Combination therapy
Smith 1999	Not an RCT
Tzachev 2002	Participants had allergic rhinitis
Weisberg 1966	Combination therapy
Winther 1983	Nasal airway resistance was not measured; the weight of nasal discharge was measured
Zumpft 1975	Participants had allergic rhinitis

RCT: Randomised controlled trial