The acute effects of ethanol (ETOH), injected at 3 g.kg −1i.p. on spontaneous contractions, on prostaglandin (PG) production and on the metabolism of triglycerides (TGs), have been studied in uterine strips obtained from rats at diestrus and suspended in glucose-containing or glucose-free solution. The absolute values of isometric developed tension (IDT: expressed in mg) recorded at 0 time (initial or post isolation determinations) and the frequency of contraction (FC), expressed as the number of contraction cycles during 20 min, were similar for uterine strips from controls and from ETOH treated rats. The uterine IDT and the FC expressed as percent changes from internal controls (0 time values) were explored during 180 min in uteri suspended in glucose medium. The magnitude of IDT decreased, as time progressed, both in controls as well as in ETOH-treated rats. Afterwards, uterine strips from controls exhibited a partial recovery of their contractile activity. This pattern of recovery was not observed in uterine strips from ETOH-treated rats. The uterine IDT, in the ETOH-injected animals after 180 min of activity, were significantly smaller than those of controls. On the other hand, the FC decreased progressively up to the end of the experimental period both in controls as well as in ETOH-treated rats. In glucose-free medium, the IDT of uterine strips from ETOH-injected animals diminished significantly more than controls from 100–180 min following isolation and mounting. In addition, the FC of uterine strips from the ETOH group of rats were significantly smaller than in controls suspended in glucose-free solution. Regarding the production of PGs, it was observed that at 180 min following isolation, uterine strips suspended in glucose-containing medium released similar amounts of PGE 1 and PGE 2 in controls as in the ETOH. However, when preparations of the last group were kept in glucose-free medium, the release of PGE 1 from the tissue was significantly higher than the output of PGE 2. Uterine tissue obtained from controls released similar amounts of PGE 1 and of PGE 2 into the incubating medium, also in the absence of external glucose. The absolute levels of TGs in uteri obtained from ETOH rats, were significantly greater than in controls. On the other hand, TG levels found in isolated rat uteri suspended in glucose solution, did not differ either at 0 min or at 180 min in tissues from control rats, whereas uterine TGs from ETOH-treated animals were significantly lower after 180 min than at 0 time. Furthermore, in preparations suspended in glucose-free medium, TG levels determined at 180 min exhibited significantly smaller concentrations than at 0 time in uteri from controls and from ETOH-exposed animals. Finally, we have studied the time-dependent increment of uterine and plasma TGs after the acute injection of ETOH. It was found that plasma TG values were significantly enhanced at 15 min after the injection whereas at 30 min the concentration of TGs had returned to their basal levels. On the contrary, at 15 min following ETOH, uterine levels of TGs were similar to controls assessed prior to the injection, and became significantly higher at 30 min after ETOH. Summarizing, the present study demonstrates that after a single injection of ETOH the IDT of uterine strips decreased significantly, as did the levels of TGs in tissue preparations kept in a medium with or without glucose as the external substrate.