A system and a method used to select a suitable inhaler for a patient based on readings provided by the user. The system consists of a computer and a spirometer, with a data connection between them. The spirometer records the inhalation flow 54, 56 of the patient and this data is sent to the computer where this data is compared with pre-recorded dose emission flow data 40 sourced from a range of inhalers. The inhaler with the largest medicine emission flow 40 within 44, 46 the inhalation flow 54, 56 is indicated as the suitable inhaler. The dose emission flow 40, inhalation flow 54, 56, and recommended inhaler are displayed by the computer. Messages are displayed advising patients on how to improve inhalation techniques to increase the uptake of medicine. The flow resistance of the different inhalers is simulated by adjusting the flow through a mouthpiece of the spirometer. The computer may be either a mobile phone, a mobile computer, a laptop, a tablet, a PC, a watch, or a cloud service.
