The horse chestnut plant is well-known to be toxic as it contains the toxic chemical aesculin. It therefore cannot be taken raw and would always need to be removed before it can be used for medicinal purposes. This herb has actually been classified as an unsafe herb by the FDA because of this.26 However, standardized horse chestnut seed extract which has β-aescin as its active ingredient is generally considered to be safe. Some minor side effects have been reported including gastrointestinal problems, diarrhea, feeling ill, having stomach upsets and skin reactions such as itching, rash and urticaria. Some more serious side effects have also been reported including kidney problems, weakness, muscle twitching, loss of coordination, vomiting,
