I was at one time very constipated.
Imagine having impacted stools? It was quite scary.
Then I tried lactulose which is quite a mild laxative.
Initially, one may have to take about thirty mililiters but the subsequent dose can be reduced; just use trial and error (the leaflet will have instructions for you)
I have now stopped this regimen and have resorted to a more "natural" method.
Every morning, after getting up, I drink two glasses of water (on an empty stomach).
Throughout the day, I drink as many glasses of water as I can tolerate which much more than the proverbial eight glasses. I imagine I have water up to my eyeballs!
Next, take high fiber foods, like high fiber bread (bake your own if you cannot find any on the market). Note, after eating any food, drink a glass of water. This will help the food go down and provide water for the fiber. Note that eating plenty of fiber but drinking little water can exacerbate the problem.
Take plenty of fruits and vegetables, especially those with plenty of fiber.
Finally, don't give up the regime too easily.
Hope this will help.