Poor blood flow in the veins of the legs, known as chronic venous insufficiency, is a common health problem, particularly with ageing. It can cause leg pain, swelling (oedema), itchiness (pruritus) and tenseness as well as hardening of the skin (dermatosclerosis) and fatigue. Wearing compression stockings or socks helps but people may find them uncomfortable and do not always wear them. A seed extract of horse chestnut (Aesculus hippocastanum L.) is a herbal remedy used for venous insufficiency. Seventeen randomized controlled trials were included in the review. In all trials the extract was standardised to escin, which is the main active constituent of horse chestnut seed extract.
Overall, the trials suggested an improvement in the symptoms of leg pain, oedema and pruritus with horse chestnut seed extract when taken as capsules over 2 to 16 weeks. Six placebo-controlled studies (543 participants) reported a clear reduction of leg pain when the herbal extract was compared with placebo. Similar results were reported for oedema, leg volume, leg circumference and pruritis. The other studies which compared the extract with rutosides (four trials), pycnogenol (one trial) or compression stockings (two trials) reported no significant differences between the therapies for leg pain or a symptom score that included leg pain. The herbal extract was equivalent to rutosides, pycnogenol and compression on the other symptoms with the exception that it was inferior to pycnogenol on oedema.
The adverse events reported (14 trials) were mild and infrequent. They included gastrointestinal complaints, dizziness, nausea, headache and pruritus, from six studies.