In dental surgery, the negative effects that can be caused by the dentist are classified as therapeutic and behavioural. The anamnesis and the superficial clinical examination, an incomplete diagnosis or improper therapy may lead to negative results. In many cases, the negative behaviour of the dentist or his team may have a strong psychological impact on some patients. For the material and method section regarding this subject, the author, member of the Dental Association of Timiş Country, has studied 24 files with complaints against general practitioners. The results of his study are presented objectively and the types of the complaints are classified on a scientific basis. The conclusions demonstrate the strong impact that the doctor’s behaviour may have on his patients. In the end, the paper describes a positive type of attitude towards the patients that all doctors should adopt, irrespective of their age.