Four gallic acid solns. (0.2 and 1.0 mg/mL) prepd. on the basis of H2O or MeOH were subjected to ultrasounds (frequency 20 kHz, intensity 21 or 38 W/cm(2), time 0-30 min). A slight but statistically significant degrdn. of gallic acid was obsd. only for its MeOH solns., esp. for the concn. of 0.2 mg/mL and the treatment time of 30 min. Ultrasounds did not change the oxidative activity of the tested solns.