In a letter Friday, W.F. Burns Middle School Principal Priscella Holley asked parents to have each student bring a canned item.
"We realize at first this may seem odd; however, it is a practice that would catch an intruder off guard," she wrote in the letter, published by TV station WHNT.
"The canned food item could stun the intruder or even knock him out until the police arrive," Holley wrote.
The letter was sent after school employees received training from Auburn University's Department of Public Safety, Chambers County Schools Superintendent Kelli Hodge told The Associated Press on Tuesday.
Using cans or other items as weapons would be a last resort for students unable to evacuate, Hodge said.
Teachers are taught to barricade classroom doors if an intruder is in the school, but if that fails, the cans and items such as textbooks could be used, she said.
"If somebody is going to force their way through, then as the last resort you would start throwing any objects you could get your hands on," Hodge said.