BACKGROUND AND OBJECTIVE: Pimpinella anisum is a medicinal herb widely used in the traditional Iranian medicine to cure digestive, inflammatory, and spastic diseases. This study aimed to evaluate the analgesic effects of methanol extract of Pimpinella anisum.L in mature male Wistar rats.

METHODS: In this study, 48 male Wistar rats were divided into 8 groups of control, treated with the Pimpinella anisum.L extract (50, 100, 200 mg/kg), treated with morphine, aspirin, extract with naloxone and extract with aspirin. Extraction was performed via maceration, rating and tail flick tests. In addition, formalin tests were conducted to evaluate the analgesic effects of the extract, and all the injections were performed intraperitoneally.

FINDINGS: Co-administration of 200 mg/kg of Pimpinella anisum.L extract combined with aspirin was observed to produce significant analgesic effects (p<0.05) compared to aspirin alone, with a one-second reduction of time delay in the tail flick test. In the rating test, 200 mg/kg of the extract resulted in more significant analgesic effects compared to aspirin alone (p<0.01), reducing the number of abdominal contractions to 10. The acute toxicity of the extract was determined as 2125 mg/kg. 

CONCLUSION: According to the results of this study, the methanol extract of Pimpinella anisum.L could exert analgesic effects in both the acute and chronic phases of pain.