Aluminum (Al) as aluminum lactate in a purified diet was fed to adult female Swiss-Webster mice over a six week period. Comparison groups were: controls (CON), 25 micrograms Al/g diet; low Al (LO), 500 micrograms Al/g diet; high Al (HI), 1000 micrograms Al/g diet; and pair fed (PF) 25 micrograms Al/g diet pair fed to HI group. Weights, food intake and toxic signs were recorded at 3-day intervals and activity levels were measured during a 24-hr session during week 5 using an automated apparatus. Food intake was not reduced overall in Al-treated groups but they demonstrated a cyclic pattern of food intake. Mean weight gain over the 6-week period in the HI (0.5 g) and PF(0.1 g) groups was somewhat less than that in the CON (2.3 g) and LO (2.0 g) groups. No neurotoxic signs were recorded in any group, but a dose dependent increase in localized fur loss was seen. Overall activity level was 20% lower in HI than CON groups, with vertical movement more affected than horizontal movement. HI mice were less active during the diurnal period of peak activity than CON mice and their activity periods were also somewhat shorter (130 vs. 200 min). Activity of LO and PF mice did not differ significantly from controls, although PF activity levels were more variable. These data demonstrate that short term feeding of aluminum at levels within an order of magnitude of estimated human intake can influence neurobehavioral function as indexed by motor activity.