Introduction and objective:
Achalasia is a chronic disease in which the relaxation function of the muscles forming the lower esophageal sphincter is impaired and the peristalsis of the esophagus is disturbed,which leads to the retention of food content. The disease affects both genders, and can occur at any age. The aim of the study is to discuss the current knowledge on achalasia.

Review methods:
The PubMed and Google Scholar databases were used for the literature review. The following phrases were searched for in English: "achalasia", "achalasia treatment", "esophageal achalasia", "pseudo-achalasia".

Brief description of the state of knowledge:
The etiology of achalasia is complex and includes autoimmune, genetic and infectious causes. The most common symptoms of achalasia are regurgitation, chest pain, heartburn and chronić cough. The diagnosis is usually made many years after the onset of the first symptoms. Adenocarcinoma of the cardia may produce symptoms identical to those of achalasia (socalled pseudoachalasia), therefore it is important to perform a full differential diagnosis. Thetreatment of achalasia is symptomatic and aims to facilitate the passage of food through the esophagus and cardia, and thus improve the patient's quality of life. The choice of the method of treatment depends on the availability of the method in a given centre, the physician’s experience, the result of the manometry test, the condition and preferences of the patient. It should be remembered that patients with achalasia are at increased risk of developing esophageal cancer.

Summary:
Early diagnosis of achalasia allows for the implementation of appropriate treatment that improves the quality of life and reduces the risk of dangerous complications. The etiology of achalasia is not fully understood and requires further research.