Magister Chirurgiae Dentium (MChD) / Pulp therapy in the primary dentition has always been a source of much controversy. Different pulpotomy techniques and medicaments have been covered extensively in the literature but due to the increasing awareness of the potential deleterious effects of some of these medicaments, a need has arisen in the dental profession to fmd safer, alternative pulpotomy agents. Ferric sulfate and calcium hydroxide have been suggested as possible, more biologically acceptable alternatives to formocresol, which is known for its toxic side effects. Ferric sulfate is one of the most recent agents used in vital pulp therapy and has enjoyed reasonable success. Further controversy also exists in terms of the type of base which is placed over the amputated pulp. The choice of the base seems to determine the pulpal response. Two bases, calcium hydroxide (Dycal) and zinc oxide-eugenol (Kalzinol) have both been used in separate studies but have never been compared. The aim of this study is to compare the success rate obtained when applying one or the other of these two bases following a ferric sulfate pulpotomy. Presently it is unknown which base is best. In this study, after haemostasis was achieved with damp cotton pellets, ferric sulfate was applied to the pulpal stumps. Half of the cases then received a Dycal base followed by a cured layer of Vitrebond and a permanent amalgam restoration. The other half of the cases received a base of zinc oxide-eugenol (Kalzinol) followed by an amalgam restoration. Overall, teeth treated with Dycal demonstrated a higher failure rate when compared with those that received the Kalzinol base. Abscess formation and internal resorption were the most common causes of failure. Even though the Kalzinol base demonstrated greater success, there were still quite a few failures. This study demonstrates, that even with the use of a haemostatic agent, calcium hydroxide cannot be recommended as a medicament in primary tooth pulpotomies. It also highlights the need for alternative pulpotomy medicaments that are not irritating or harmful to the pulp.