This paper presents the results of research on the influence of the components of salt flame retardants on the compressive strength of wood depending on the time of accelerated aging. The effect of the agent was assessed on the basis of the change in the strength of treated wood compared to that of untreated wood. In addition, a statistical analysis of the obtained results was used to determine which of the components most significantly affect the changes in the compressive strength of wood along the fibers, and to what extent. It was found that extending the aging process time in the case of control and boric acid-protected samples did not significantly change the strength properties. It has also been found that some compounds contained in fire retardant have an antagonistic effect related to the compressive strength of wood.