How fast coconut oil will work to relieve constipation depends on how much you consume and the way you eat coconut oil. It also depends on how quickly your body responds to the bowel-loosening effect of coconut oil.
For instance, some people just need one tablespoon and in less than an hour coconut oil eases their constipation. Some may need two tablespoons for coconut oil to work quickly. And that usually occurs to those who take coconut oil on an empty stomach. When your stomach is empty, coconut oil digests and stimulates bowel movement faster.
However, eating coconut oil on an empty stomach may trigger diarrhea – opposite to constipation. Good? Not really. The diarrhea effect can last for many hours before it wears off. It's physically draining, especially for seniors.
In view of that, I suggest you take coconut oil with or after food. Though coconut oil may not work to relieve constipation as quickly you want it to, it's safer to get rid of your stubborn poop without suffering the runs.