Many herbomineral preparations are currently being used as therapeutic remedies for common ailments. Commonly known cardiotoxic herbs are Aconitum ferox (aconite), Areca catechu (betel nut), Thevetia peruviana (yellow oleander) and Cleistanus collinus (oduvan). Herbs mixed with lead, copper and/or mercury are known to be highly toxic. They produce cardiac arrhythmias, mainly ventricular ectopics, ventricular tachycardia and various degrees of arterioventricular (AV) blocks. We report 12 such successive cases where the patients developed vague feelings of discomfort, dizziness, chest discomfort and ventricular arrhythmias following herbal drug ingestion which warranted the immediate discontinuation of the drug. Three of the patients died. This paper emphasizes the risk of unsupervised use of herbomineral preparations by patients who believe that the remedies are always 'safe' and the urgent necessity for the pharmacognostic identification of the constituent herbs, their toxicological studies, uniform nomenclature, authenticity and standardization of plants and their parts before advocating them for therapeutic use.