Introduction
Paracetamol poisoning is a frequent cause of hospitalization in Denmark. On 30 September 2013, the Danish authorities restricted packages available without a prescription in pharmacy outlets to contain a maximum of 10 g of paracetamol. We aimed to investigate the effects of this regulation.

Methods
This was a cross-sectional study of two groups of patients admitted consecutively to a Danish University Hospital due to poisoning with paracetamol in 365 days in 2012–13 before 30 September 2013, and a corresponding 365-day period in 2017–18. Data were extracted from patient records.

Results
In 2012–2013 and 2017–18, 156 and 92 admissions in 127 and 78 unique patients, respectively, were identified. Ingestion of more than 20 g paracetamol occurred in a significantly higher proportion of cases in 2012–13 compared to 2017–18 (29% vs 13%, P < 0.01). In accordance, there were no cases of international normalized ratio >1.5 or alanine aminotransferase activity >1000 U/L in the post-legislation period, and seven and five cases in the pre-legislation period, respectively. Females accounted for 80% and 78% of patients in the two periods, respectively, and were considerably younger than males (median [interquartile range]: 22 [17–40] vs. 47 [30–56], P < 0.01 in 2012–13, and 23 [18–46] vs. 43 [27–49] years, P = 0.02 in 2017–18). Furthermore, in 2012-13, intentional poisonings occurred in a higher proportion of females than males 2012–13 (97% vs 85%, P < 0.01).

Conclusions
The present study demonstrated a lower number of paracetamol poisonings, a decreased proportion of poisonings involving ingestion of more than 20 g of paracetamol, and a lower occurrence of hepatotoxicity after the regulation. However, circumstances other than pack size restrictions, such as increased public awareness of the danger of paracetamol poisonings, may affect these associations. Furthermore, the study showed that females and males constitute two distinct groups in terms of age and intentional poisoning.