When ingesting Epsom Salt to use as a laxative you may notice results within 30 minutes to an hour and sometimes it may take a few hours to have the laxative begin taking an effect on your insides and start relieving your bowels.
After taking Epsom Salt you should be near the toilet just in case it begins working soon after you take it.
Epsom Salt in my experience gets my bowels moving within an hour of ingesting it so be ready to get to the toilet.
Castor Oil although nasty tasting has been in use for many years as a natural home remedy laxative and get relieve constipation within 20 to 30 minutes so if the Epsom Salt doesn't get your bowels moving then try Castor Oil as it surely will.
My mom used to give me nasty tasting Castor Oil when I was a kid and was constipated and it sure did work.