The following theorem is proved. Let m, k and n be positive integers. There exists a number η = η(m, k, n) depending only on m, k and n such that if G is any residually finite group satisfying the condition that the product of any η commutators of the form [x m , y 1 , . . . , y k ] is of order dividing n, then the verbal subgroup of G corresponding to the word w = [x m , y 1 , . . . , y k ] is locally finite.2010 Mathematics subject classification: primary 20E10; secondary 20E26, 20F40, 20F50.