My 4 Month Baby Is Not Going Motion Properly.first 2

My 4 month baby is not going motion properly.first 2 months there was no problem.now every 10 days I have to use suppository for motion.at that time normal he is doing.he is not showing any difficulty in pooping.somebody saying gripe water,lactulose soln(2ml) ,dry grape water all I tried but not working.wht should I do