Addiction is a mental and / or physical state of addiction to certain psychoactive substances, behaviors or situations. They can be different, and each has its own significance, degree of intensity, psychological, social and economic dimensions. Alcohol is considered to be the most commonly abused substance in Europe, including Croatia. No celebration from the time of the ancient Greeks and Romans until today has passed without the consumption of alcohol. Also, alcohol is considered to be the first psychoactive substance that people encounter, specifically young people aged 14 years. Alcoholism is an addiction to alcohol, while an alcoholic according to the definition of the World Health Organization is a person who has become addicted to alcohol through long-term drinking, mentally, physically or in both ways and has developed mental or physical impairments and social difficulties accessible to traditional medical and social diagnostic procedures. The clinical picture of alcoholism is first manifested in the very appearance of the alcoholic, and then in his change of personality, which in turn leads to the deterioration of their own health, relationships in the family and in society, job loss. All of the above components can contribute to the worsening of the condition. The diagnosis of alcoholism is made on the basis of anamnestic data of disease symptoms, medical examination, heteroanamnestic data, which are most often given by family members, laboratory tests and various questionnaires. Alcoholism treatment consists of treatment that includes strict abstinence and lifestyle changes, then outpatient treatment and inclusion in self-help and mutual aid groups such as Alcoholics Clubs and Alcoholics Anonymous. This paper will consist of two parts. In the first part I will define the concept of alcoholism, explain the epidemiology and etiology of alcoholism, then the effects of alcohol on the body, the clinical picture of alcoholism, diagnosis, treatment, consequences of alcoholism and the role of the nurse in people addicted to alcohol. The second part consists of a survey questionnaire conducted online using the Google Docs application. The main goal of the research was to determine whether alcoholism is still the leading harmful habit in the 21st century.