Dulcolax
"I have had constipation all my life I am now 31. When I had my children my constipation turned chronic. I tried all the normal things in the chemist. Agarol. Metamucil. Senna. Nulax. Movicol.....the list goes on.
I had a colonoscopy which confirmed nothing .
This was frustrating as I'm glad it was all clear but the nothing diagnosis didn't help me fix anything. The doctor said I have  lazy bowel as I never got the urge to go to use my bowels . 
After the children I tried dulcolax which I wanted to try earlier but couldn't because pregnant. 
My first time was horrendous haha the cramps oh my goodness but then the relief oh my was I cleaned out  felt amazing.  
Unfortunately I take 2 every night before bed and have done every day for the last 6 years ."