The aim of this study is to examine oral habits, dietary habits and the knowledge about the food harmfulness to teeth. This study included 40 randomly chosen people from Rijeka and Rovinj who do not have any professional contact with dentistry. The research has shown that, apart from dental floss which is rarely used, the majority of examinees (70%) brush their teeth twice a day, 25% of them more times per day. The majority of examinees visit a dentist once a year. But, in spite of it, 65% of them had their teeth treated in the last two years. The examinees in most cases have more than five recommended meals per day. In between-meal snacks people mostly consume sweets and bakery products. Sweets are consumed very often and not as a part of a meal (70%). A disappointing fact is the poor water consumption in favour of various different sweetened beverages, coffee and tea. Apart from caries, a frequent consumption of sweetened baverages, can lead to a dental erosion due to their high amount of acids. The examinees have shown certain knowledge about the harmfulness of carbohydrates. However, only food that is recognised as harmful, were sweets and sweetened beverages. This shows lack of information about the harmfulness of starch and other food that is not primary sweet. On the other hand, food as cheese, tea and coffee are recognised as harmful although they are not. These results show that the knowledge about correlation between caries and food is not taken seriously enough. Although people know about the harmfulness of fermentable carbohydrates, they are often present in everyday diet. Doctors of dental medicine have to point out the harmfulness of carbohydrates, especially harmfulness of their frequent consumption.