Allegra 1981.

Study characteristics
Methods	Study design: randomised, double‐blind, placebo‐controlled Method of randomisation: table of random numbers Exclusions post randomisation: none Losses to follow‐up: none
Participants	Country: Italy Setting: hospital Number: 80 patients Age: not stated Gender: not stated Inclusion criteria: patients with postphlebitic syndrome, oedema of the lower limb, phlebolymphoedema, constitutional venous stasis, varices Exclusion criteria: not stated
Interventions	Treatment: 2 × 10 mg Centella tablets 3 × per day Control: placebo Duration: 30 days Follow‐up: 30 days
Outcomes	Primary Symptoms ‐ heavy legs, pain, cramps, global assessment by participant and by physician measured by an ordinal scale (0 to 3) Signs ‐ leg oedema, venous dilatation and skin trophism measured by an ordinal scale (0 to 3). Venous pressure measured by echo Doppler Secondary Tolerance
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The assignment of patients to one of two treatments, labelled as A or B, was made randomly using a special randomization list" Comment: a randomisation list is generally accepted as a fair method of ensuring a random sequence
Allocation concealment (selection bias)	Unclear risk	Comment: no information given about methods used for allocation concealment
Blinding (patients)	Unclear risk	Comment: no information given about methods used for blinding
Blinding (study researchers)	Unclear risk	Comment: no information given about methods used for blinding
Blinding (outcome assessment)	Unclear risk	Comment: no information given about methods used for blinding
Incomplete outcome data	Low risk	Comment: no exclusions post randomisation and no losses to follow‐up
Selective reporting	Unclear risk	Comment: the number of participants in both groups was described. However, a table with important characteristics was lacking; this could lower the generalisability. Adverse events, tolerability and signs of intolerance were presented
Other bias	Low risk	Comment: none detected