The invention relates to the monitoring of products by means of active radio tags. According to the invention, packagings of products are provided with an active radio tag that detects at least one environmental condition and/or at least one packaging state, and which emits a signal at time intervals, which provides information about a unique identifier and at least one state in which the respective product is found. The signal is picked up by a receiver that extracts the unique identifier and the state information and transmits same together with location information to an external server.