The aim of this study was to determine the influence of prostaglandin F₂α (PGF₂α) on the contractile activity of intact and inflamed porcine uteri. On day 3 of the oestrous cycle, gilts were randomly assigned to group I (control; n = 6) or II (treated with E. coli; n = 6). In all gilts median laparotomy was performed and 50 ml of saline or 50 ml of E. coli containing 10⁹ colony-forming units/ml were injected into each uterine horn in groups I and II, respectively. After seven days (on day 10 of the oestrous cycle) the gilts were slaughtered and uterine horns collected. After macroscopic examination, contractile activity of uterine strips: endometrium+myometrium (ENDO/MYO) and myometrium (MYO) was examined using noradrenaline (NA), acetylocholine (ACh), PGF₂α alone or together with EP₂,EP₄, EP₁, EP₃ receptor blockers (BEP₂, BEP₄, BEP₁ and BEP₃, respectively). NA decreased (P<0.01, P<0.001) the intensity of contractions in ENDO/MYO and MYO of the control group but increased (P<0.05, P<0.01) in the inflamed uterus. ACh at doses 10^-5, 10^-4 and 10^-3 M increased (P<0.05-0.001) the intensity of contractions in ENDO/MYO and MYO from the bacteria group and intact group (P<0.05) at doses10^-4 and 10^-3 M. ACh at all of the tested doses increased (P<0.05-0.001) the frequency of contractions in the control and decreased (P<0.05, P<0.001) in the experimental group. NA and ACh treatment revealed that uterine strips were living and suitable for further investigations. PGF₂α at a dose of 10^-7 M increased (P<0.05, P<0.01) the intensity of contractions in ENDO/MYO and MYO in both control and experimental groups. PGF₂α at doses 10^-8 and 10^-7 M used in the presence of BEP₂ or BEP₄ increased (P<0.05-0.001) the intensity of contrac- tions in both the control and bacterial groups. However, PGF₂α did not significantly influence the frequency of contractions with the exception of the stimulatory effect in ENDO/MYO (P<0.001) strips of the control groups. PGF₂α at doses of 10^-8 and 10^-7 M administered after BEP₁ and BEP₃ treatment decreased (P<0.05-0.001) or did not significantly influence the intensity and frequency of contractions in uterine tissues in both examined groups. The presented findings revealed that PGF₂α, besides affecting the contractile activity of uterine tissues, may also act through the PGE₂ receptors. However, thorough interpretation of these results requires determination of the role of other prostanoids in this process.