Abstract: Flow restriction to be fitted in a fluid line, consisting of a conduit part that has been produced from plastic by injection moulding and has been provided with a baffle closing the flow cross-section, wherein one or more openings have been made with the aid of a laser treatment. Each of these openings has a diameter of between 1 and 50 ?m. It has been found that, when a large number of openings are used, if one of the openings becomes blocked for whatever reason this has hardly any effect on the total flow cross-sectional surface area. It is consequently possible to determine the flow conditions in the restriction very accurately and very reproducibly and consequently to establish the flow characteristics accurately. Such a flow restriction can be used, for example, in applications for dosing medication.