The effects of adafenoxate (Adf), meclofenoxate (Mf), piracetam (Pc), and citicholine (CCh) on scopolamine (Scop)--impaired memory and exploratory behavior (experiments on rats) and on physical capabilities (experiments on mice) were studied. In the experiments with scopolamine (2 mg/kg i.p.) we used the step-through passive avoidance method to determine the memory changes. In the case of single treatment with the drugs tested scopolamine was injected immediately after training and Adf, Mf, and CCh at doses of 20 and 100 mg/kg and Pc at a dose of 100 mg/kg were administered immediately after scopolamine. In the case of multiple administration the drugs were applied at the same doses for 7 days before training. Scopolamine was injected immediately after training. Retention tests were given 3 and 24 hours later. All the four drugs tested prevented to a large extent or completely the scopolamine-induced retrograde amnesia. However, significant quantitative differences in the antiamnestic effects of the drugs tested were observed. The effects of the four drugs on exploratory behavior were tested in the Opto Varimex apparatus. After 7-day treatment with the drugs at the doses utilized, the behavior of experimental animals was observed for 10 min, checking out the changes in the frequency of rearing, ambulation, and rotation. Only Adf at a dose of 50 mg/kg significantly decreased rearing and ambulation frequencies; this effect was considered to be an expression of accelerated habituation. The physical capabilities of mice were studied, using the method of treadmill (revolving drum activity cage) training. Before the experiment the mice received orally Adf, Mf, and Pc at a dose of 100 mg/kg or were injected intraperitoneally with CCh at doses of 50 and 100 mg/kg once daily for 7 days. The number of revolutions of the drum cages was counted for 4 hours. Only Pc significantly increased the physical capabilities of mice and much delayed the occurrence of fatigue.