The article deals with the latest amendment to the Pharmaceutical Law Act, dated 13 July 2023, which is related to anticoncentration restrictions on the issuance of licenses to run generally accessible pharmacies. On 4 October 2023, the President of the Republic of Poland, pursuant to Article 191 section 1 item 1 of the Constitution of the Republic of Poland, filed a motion to examine the constitutionality of this amendment. In the motion, the President argued that the amendment intro-duces a new ban on pharmacy market concentration (Article 99 section 3aa of the Pharmaceutical Law), which was introduced in violation of the principle of protec-tion of acquired rights and without adequate vacatio legis. In light of the President’s motion, the subject of this article is an analysis of the provisions of the amendment with regard to the changes involving the addition of sections 3aa and 3ab under Article 99 and sections 2a-2d under Article 103 of the Pharmaceutical Law in order to determine their legal nature, comply with the principle of protection of acquired rights, and to decide whether the adopted vacatio legis period is appropriate.