An herbal/bicarbonate toothpaste has received some attention from the public and profession following a number of studies which have reported beneficial effects of the paste on both plaque and gingivitis. The present study, one of several ongoing clinical trials, evaluated the toothpaste in mouthrinse form using a 19-day, no oral hygiene, triple-crossover design in which it was compared with a commercial fluoride toothpaste rinse and the antiplaque mouthrinse chlorhexidine. Over the three periods of the study an increase in plaque and gingivitis was seen for all three products. However, while significant reductions in both parameters were seen with chlorhexidine compared to the toothpastes, there were no significant differences between the herbal and fluoride toothpaste. From these findings it can be concluded that in the long term, the herbal/bicarbonate toothpaste may not exert significant therapeutic effects on plaque and gingivitis beyond that of a conventional commercial paste. Nevertheless, where there is a demand for a natural product, the herbal/bicarbonate paste may be a worthwhile alternative.