Background: Telangiectasias (spider veins) and reticular veins on the lower limbs are very common, increase with age, and have been found in 41% of women. The cause is unknown and the patients may be asymptomatic or can report pain, burning or itching. Treatments include sclerotherapy, laser, intense pulsed light, microphlebectomy and thermoablation, but none is established as preferable., Objectives: To assess the effects of sclerotherapy, laser therapy, intensive pulsed light, thermocoagulation, and microphlebectomy treatments for telangiectasias and reticular veins., Search Methods: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, AMED and CINAHL databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 16 March 2021. We undertook additional searches in LILACS and IBECS databases, reference checking, and contacted specialists in the field, manufacturers and study authors to identify additional studies., Selection Criteria: We included randomised controlled trials (RCTs) and quasi-RCTs that compared treatment methods such as sclerotherapy, laser therapy, intensive pulsed light, thermocoagulation, and microphlebectomy for telangiectasias and reticular veins in the lower limb. We included studies that compared individual treatment methods against placebo, or that compared different sclerosing agents, foam or laser treatment, or that used a combination of treatment methods., Data Collection and Analysis: Three review authors independently performed study selection, extracted data, assessed risks of bias and assessed the certainty of evidence using GRADE. The outcomes of interest were resolution or improvement (or both) of telangiectasias, adverse events (including hyperpigmentation, matting), pain, recurrence, time to resolution, and quality of life., Main Results: We included 3632 participants from 35 RCTs. Studies compared a variety of sclerosing agents, laser treatment and compression. No studies investigated intensive pulsed light, thermocoagulation or microphlebectomy. None of the included studies assessed recurrence or time to resolution. Overall the risk of bias of the included studies was moderate. We downgraded the certainty of evidence to moderate or low because of clinical heterogeneity and imprecision due to the wide confidence intervals (CIs) and few participants for each comparison. Any sclerosing agent versus placebo There was moderate-certainty evidence that sclerosing agents showed more resolution or improvement of telangiectasias compared to placebo (standard mean difference (SMD) 3.08, 95% CI 2.68 to 3.48; 4 studies, 613 participants/procedures), and more frequent adverse events: hyperpigmentation (risk ratio (RR) 11.88, 95% CI 4.54 to 31.09; 3 studies, 528 participants/procedures); matting (RR 4.06, 95% CI 1.28 to 12.84; 3 studies, 528 participants/procedures). There may be more pain experienced in the sclerosing-agents group compared to placebo (SMD 0.70, 95% CI 0.06 to 1.34; 1 study, 40 participants; low-certainty evidence). Polidocanol versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD 0.01, 95% CI -0.13 to 0.14; 7 studies, 852 participants/procedures), hyperpigmentation (RR 0.94, 95% CI 0.62 to 1.43; 6 studies, 819 participants/procedures), or matting (RR 0.82, 95% CI 0.52 to 1.27; 7 studies, 859 participants/procedures), but there were fewer cases of pain (SMD -0.26, 95% CI -0.44 to -0.08; 5 studies, 480 participants/procedures) in the polidocanol group. All moderate-certainty evidence. Sodium tetradecyl sulphate (STS) versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD -0.07, 95% CI -0.25 to 0.11; 4 studies, 473 participants/procedures). There was more hyperpigmentation (RR 1.71, 95% CI 1.10 to 2.64; 4 studies, 478 participants/procedures), matting (RR 2.10, 95% CI 1.14 to 3.85; 2 studies, 323 participants/procedures) and probably more pain (RR 1.49, 95% CI 0.99 to 2.25; 4 studies, 409 participants/procedures). All moderate-certainty evidence. Foam versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD 0.04, 95% CI -0.26 to 0.34; 2 studies, 187 participants/procedures); hyperpigmentation (RR 2.12, 95% CI 0.44 to 10.23; 2 studies, 187 participants/procedures) or pain (SMD -0.10, 95% CI -0.44 to 0.24; 1 study, 147 participants/procedures). There may be more matting using foam (RR 6.12, 95% CI 1.04 to 35.98; 2 studies, 187 participants/procedures). All low-certainty evidence. Laser versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD -0.09, 95% CI -0.25 to 0.07; 5 studies, 593 participants/procedures), or matting (RR 1.00, 95% CI 0.46 to 2.19; 2 studies, 162 participants/procedures), and maybe less hyperpigmentation (RR 0.57, 95% CI 0.40 to 0.80; 4 studies, 262 participants/procedures) in the laser group. All moderate-certainty evidence. High heterogeneity of the studies reporting on pain prevented pooling, and results were inconsistent (low-certainty evidence). Laser plus sclerotherapy (polidocanol) versus sclerotherapy (polidocanol) Low-certainty evidence suggests there may be more resolution or improvement (or both) of telangiectasias in the combined group (SMD 5.68, 95% CI 5.14 to 6.23; 2 studies, 710 participants), and no clear difference in hyperpigmentation (RR 0.83, 95% CI 0.35 to 1.99; 2 studies, 656 participants) or matting (RR 0.83, 95% CI 0.21 to 3.28; 2 studies, 656 participants). There may be more pain in the combined group (RR 2.44, 95% CI 1.69 to 3.55; 1 study, 596 participants; low-certainty evidence)., Authors' Conclusions: Small numbers of studies and participants in each comparison limited our confidence in the evidence. Sclerosing agents were more effective than placebo for resolution or improvement of telangiectasias but also caused more adverse events (moderate-certainty evidence), and may result in more pain (low-certainty evidence). There was no evidence of a benefit in resolution or improvement for any sclerosant compared to another or to laser. There may be more resolution or improvement of telangiectasias in the combined laser and polidocanol group compared to polidocanol alone (low-certainty evidence). There may be differences between treatments in adverse events and pain. Compared to other sclerosing agents polidocanol probably causes less pain; STS resulted in more hyperpigmentation, matting and probably pain; foam may cause more matting (low-certainty evidence); laser treatment may result in less hyperpigmentation (moderate-certainty evidence). Further well-designed studies are required to provide evidence for other available treatments and important outcomes (such as recurrence, time to resolution and delayed adverse events); and to improve our confidence in the identified comparisons., (Copyright © 2021 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.)