i do not know your age or the type of abdominal surgery that you had so the best patient-specific advice would come directly from the surgeon. someone who knows you your medical history etc. stool softeners tend to be better but if your surgeon's instruction recommended a laxative (many can be harsh and not appropriate for a post-surgical patient) the surgeon is the one that should specifically recommend one for you.
what laxative should i take after abdominal surgery? . there are many options otc and discharge instructions just say "laxative".