BACKGROUND.: A high homocysteine level is associated with an increased risk of ischaemic heart disease. Folate therapy has shown to reduce the homocysteine blood level, but does it decrease the risk of coronary restenosis in patients with coronary arterial disease? METHODS.: A systematic online literature search followed by a critical appraisal resulted in three suitable articles to provide an evidence-based evaluation of this clinical query. RESULTS.: The rate of coronary restenosis was reduced after folate therapy, except in patients who have had coronary stenting. An adverse effect of folate therapy on in-stent coronary restenosis was observed. CONCLUSION.: The effects of folate therapy on the rate of coronary restenosis after balloon angioplasty are contradicting. Until more clinical research has been preformed we recommend a conservative attitude towards folate therapy. (Neth Heart J 2007;15:12-5.).