Estimating the (potential) level of intoxication resulting from consumption of different foodstuffs and parapharmaceuticals is a common problem in expert opinions in forensic toxicology, because of so-called residual alcohol. In the present work, the authors compared results obtained using the Alkometr A2.0 and the Alco-Sensor, two of the most popular breathalysers. Breath analyses were conducted after consumption of chocolates filled with alcohol, a medicine for gastric pain (“gastric drops”), a breath freshener, a non-alcoholic beer and Bosman beer (6.7% alc. v/v). Ten healthy adult volunteers (5 males and 5 females) were involved in the experiment. Preliminary results allowed us to approximate the time of complete elimination of ethanol from the body after exposure to the above mentioned alcohol-containing products. Particular attention was paid to the presence of residual alcohol in the mouth. Intake of products containing alcohol may lead to positive readings of breathalysers up to 7 min. In contrast to Alco-Sensor, Alkometr A 2.0 did not reveal residual alcohol. This preliminary experiment indicated the importance of a time delay in breath analysis, and the fact that knowledge on this topic is necessary to prepare correct opinions.