House dust mite allergy is a serious problem that affects about six million people in Poland and if left untreated could be the reason for the development of bronchial asthma. The main purpose of this study was to analyse how aware the patients in the respiratory ward were about the prevention of allergic diseases caused by house dust mites and the prophylactic measures that can be taken. The study took place between September 2018 and November 2018 and involved 109 patients, hospitalised in the Respiratory Ward of the Railway Hospital in Wilkowic-Bystra, who had been diagnosed with asthma and house dust mite allergy. People between 51 and 60 years of age comprised the largest group of respondents. A diagnostic survey method was utilised for the study, whereby the survey data was collected by way of a questionnaire completed by the participants. Most people (45.0%) experience an increase in allergy symptoms when cleaning the house and when sleeping at night (35.0%). Over half of the respondents (59.0%) believe, that the main places in which dust mites are found in the home are rugs, blankets and bedding. According to respondents (40.0%), prophylactic treatments against dust mite allergy at home are effective in alleviating the symptoms. Most respondents use preventive measures to combat house dust mites and relieve allergy symptoms. The main source of information about the prevention of allergic diseases is a doctor.