OBJECTIVE To analyse reports of suspected adverse reactions in the use of herbal remedies in the Netherlands. METHODS Descriptive, retrospective. METHODS All reports of suspected adverse reactions to herbal remedies in the database of the Netherlands Pharmacovigilance Centre Lareb during the period 1991 - March 2013 were assessed on causal link between use of the medication and the reported adverse reaction. Adverse reactions were classified by severity according to international standards. An overview was made of all reports of severe adverse reactions. RESULTS The Lareb database contained 336 reports of suspected adverse reactions to herbal remedies. Of the 336 herbal remedies in the reports, 247 cases contained a single herbal ingredient. In total, the herbal remedies contained 221 different herbs, some ingredients being used in multiple products. 518 adverse reactions to the use of various herbal remedies were reported. Fifty-five reports were classified as serious. CONCLUSIONS Herbs can cause adverse reactions or interactions with medicinal products, but herbal remedies can also be adulterated with regular medicines or illegal - even toxic - ingredients. Reporting adverse reactions significantly contributes to our knowledge about this subject. Physicians and pharmacists should ask patients about the use of alternative medications, particularly those based on herbs.