The importance of ordering drugs from online pharmacies in Germany is increasing constantly. At the same time, there are many online pharmacies that try to increase their own market share through advertising. In Germany, the advertising of drugs is regulated by the Therapeutic Products Advertising Act (Heilmittelwerbegesetz (HWG)) and must therefore also be complied with by online pharmacies in their product catalogues. One important purpose of the HWG is to protect consumers by ensuring that they are presented with all necessary medical-pharmacological information about the advertised product. This paper examines the implementation of as well as the compliance with Section 4 of the HWG in the product catalogues of two online pharmacies. For this purpose, the spring/summer catalogue of 2023 was considered in the allergy, cold and gastrointestinal tract categories, resulting in the inclusion of 143 drugs from online pharmacy 1 (OP1) and 102 drugs from online pharmacy 2 (OP2) for the analysis. The information on the drugs was taken from the respective catalogue and the pharmaceutical index ‘Gelbe Liste’, collected in tabular form and was encoded. Subsequently, the required mandatory information according to Section 4 was checked by comparing the collected information with the information from the package leaflet. The analysis revealed that both catalogues insufficiently complied with Section 4 of the HWG. OP1 complied with 75% of the mandatory information required under Section 4 of the HWG and OP2 with 64%. In the OP1 catalogue, there is no indication for 6% of the drugs and no specification for 29% of the traditionally registered drugs. In addition, the mandatory notice on risks and adverse effects in the OP1 catalogue is not presented in a consumer-friendly way. In the OP2 catalogue, further concerns about the compliance with the HWG were raised due to the missing indication for 17% of the drugs, no warning for 64% of the ethanol-containing drugs and no active ingredient for 31% of the monopreparations. The insufficient compliance with the HWG in the product catalogues of OP1 and OP2 means that consumer protection as a stated objective of the HWG cannot be guaranteed. Advertising for drugs should only be possible under the condition that the content of the advertisement complies with the HWG. Insufficient compliance, as in the product catalogue of OP1 and OP2, should be prohibited as it directly contradicts the law’s objective.