There are many studies and reviews of the relationship between the asthma disease in young individuals on the one hand and caries and dental erosion on the other. The causes of caries and dental erosion might be related to the asthmatic drugs, low pH and the sweeteners that the inhaled drug contains and perhaps even the lifestyle of children and adolescents with asthma. The main focus of this review is therefore to describe various preventive strategies, based on long experience of preventive dental care in Sweden. Two fact boxes are presented, one on fluoride toothpaste as a population-based intervention for different ages and one on diet counselling in children and adolescents with asthma. The most important thing is to introduce fluoride toothpaste early in the child's life and that the parents brush the child's teeth twice a day, in the morning after breakfast and at night before bedtime, up to the age of 10. Moreover, a high-risk approach with an additional fluoride supply at home is presented, together with the application of fluoride varnish at the clinic. Regarding diet counselling, it is important to make sure that the child has regular meals during the day, maximum five to six times a day, to allow the teeth to rest between meals and restrict sweets and soft drinks to once a week. It is important to identify children and adolescents with asthma as early as possible and to refer them to a dental team for preventive treatment.